<?xml version="1.0" encoding="utf-8"?>
<!--XBRL document created with Toppan Merrill Bridge  11.4.0.1 -->
<!--Based on XBRL 2.1-->
<!--Created on: 8/12/2026 11:58:08 PM-->
<!--Modified on: 8/12/2026 11:58:08 PM-->
<link:linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance">
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#StatementCondensedConsolidatedBalanceSheets" roleURI="http://www.novelos.com/role/StatementCondensedConsolidatedBalanceSheets" />
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#StatementCondensedConsolidatedStatementsOfOperations" roleURI="http://www.novelos.com/role/StatementCondensedConsolidatedStatementsOfOperations" />
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#StatementCondensedConsolidatedStatementsOfCashFlows" roleURI="http://www.novelos.com/role/StatementCondensedConsolidatedStatementsOfCashFlows" />
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#DisclosureLeasesMaturitiesOfShortTermAndOperatingLeasesDetails" roleURI="http://www.novelos.com/role/DisclosureLeasesMaturitiesOfShortTermAndOperatingLeasesDetails" />
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#DisclosureLeasesShortTermLeasesAndOperatingLeaseLiabilitiesDetailsCalc2" roleURI="http://www.novelos.com/role/DisclosureLeasesShortTermLeasesAndOperatingLeaseLiabilitiesDetailsCalc2" />
  <link:roleRef xlink:type="simple" xlink:href="clrb-20260630.xsd#DisclosureOperatingSegmentDetails" roleURI="http://www.novelos.com/role/DisclosureOperatingSegmentDetails" />
  <link:arcroleRef arcroleURI="https://xbrl.org/2023/arcrole/summation-item" xlink:type="simple" xlink:href="https://www.xbrl.org/2023/calculation-1.1.xsd#summation-item" />
  <link:calculationLink xlink:role="http://www.novelos.com/role/StatementCondensedConsolidatedBalanceSheets" xlink:type="extended" xlink:title="995200100 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent_639221758879452329" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent_639221758879452329" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_639221758879452329" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_639221758879452329" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_639221758879452329" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_639221758879452329" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_639221758879452329" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_639221758879452329" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_639221758879452329" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_639221758879452329" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_639221758879609174" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="us-gaap_OtherAssetsNoncurrent_639221758879609174" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639221758879609174" xlink:to="us-gaap_LiabilitiesCurrent_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_639221758879609174" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="us-gaap_DerivativeLiabilitiesCurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_639221758879609174" xlink:to="us-gaap_DerivativeLiabilitiesCurrent_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_639221758879609174" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_639221758879609174" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_Liabilities_639221758879609174" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquity_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639221758879609174" xlink:to="us-gaap_PreferredStockValue_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639221758879609174" xlink:to="us-gaap_CommonStockValue_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639221758879609174" xlink:to="us-gaap_AdditionalPaidInCapital_639221758879609174" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_639221758879609174" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_639221758879609174" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_639221758879609174" order="3" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.novelos.com/role/StatementCondensedConsolidatedStatementsOfOperations" xlink:type="extended" xlink:title="995200200 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639221758879609174" xlink:to="us-gaap_NonoperatingIncomeExpense_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="us-gaap_FairValueAdjustmentOfWarrants_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense_639221758879609174" xlink:to="us-gaap_FairValueAdjustmentOfWarrants_639221758879609174" order="1" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense_639221758879609174" xlink:to="us-gaap_InterestIncomeExpenseNonoperatingNet_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_639221758879609174" xlink:to="us-gaap_OperatingIncomeLoss_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpenses" xlink:label="us-gaap_CostsAndExpenses_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss_639221758879609174" xlink:to="us-gaap_CostsAndExpenses_639221758879609174" order="1" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="us-gaap_ResearchAndDevelopmentExpense_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses_639221758879609174" xlink:to="us-gaap_ResearchAndDevelopmentExpense_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_CostsAndExpenses_639221758879609174" xlink:to="us-gaap_GeneralAndAdministrativeExpense_639221758879609174" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.novelos.com/role/StatementCondensedConsolidatedStatementsOfCashFlows" xlink:type="extended" xlink:title="995200400 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" order="1" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_NetIncomeLoss_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_DepreciationAndAmortizationOfAssets" xlink:label="clrb_DepreciationAndAmortizationOfAssets_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="clrb_DepreciationAndAmortizationOfAssets_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_ShareBasedCompensation_639221758879609174" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="us-gaap_FairValueAdjustmentOfWarrants_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_FairValueAdjustmentOfWarrants_639221758879609174" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_IncreaseDecreaseInOperatingLeaseRightOfUseAsset" xlink:label="clrb_IncreaseDecreaseInOperatingLeaseRightOfUseAsset_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="clrb_IncreaseDecreaseInOperatingLeaseRightOfUseAsset_639221758879609174" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_639221758879609174" order="6" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_639221758879609174" order="7" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="us-gaap_IncreaseDecreaseInOperatingLeaseLiability_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities_639221758879609174" xlink:to="us-gaap_IncreaseDecreaseInOperatingLeaseLiability_639221758879609174" order="8" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities_639221758879609174" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_639221758879609174" order="1" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_639221758879609174" order="3" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ProceedsFromIssuanceOfCommonStockAndWarrantsNet" xlink:label="clrb_ProceedsFromIssuanceOfCommonStockAndWarrantsNet_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639221758879609174" xlink:to="clrb_ProceedsFromIssuanceOfCommonStockAndWarrantsNet_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ProceedsFromWarrantExercisesNetOfCosts" xlink:label="clrb_ProceedsFromWarrantExercisesNetOfCosts_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities_639221758879609174" xlink:to="clrb_ProceedsFromWarrantExercisesNetOfCosts_639221758879609174" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.novelos.com/role/DisclosureLeasesMaturitiesOfShortTermAndOperatingLeasesDetails" xlink:type="extended" xlink:title="99940802 - Disclosure - LEASES - Maturities of Short Term and Operating Leases (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_639221758879609174" order="2" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_639221758879609174" order="3" use="optional" weight="1" priority="2" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_639221758879609174" order="4" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_639221758879609174" order="5" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" xlink:label="clrb_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="clrb_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_639221758879609174" order="6" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.novelos.com/role/DisclosureLeasesShortTermLeasesAndOperatingLeaseLiabilitiesDetailsCalc2" xlink:type="extended" xlink:title="40802 - Disclosure - LEASES - Short-term leases and operating lease liabilities (Details) Calc2">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_639221758879609174" order="1" use="optional" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_OperatingLeaseLiability_639221758879609174" order="2" use="optional" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:role="http://www.novelos.com/role/DisclosureOperatingSegmentDetails" xlink:type="extended" xlink:title="99940901 - Disclosure - OPERATING SEGMENT (Details)">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_3" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentDirectExpensePhase2StudyInCloverWam" xlink:label="clrb_ResearchAndDevelopmentDirectExpensePhase2StudyInCloverWam_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentDirectExpensePhase2StudyInCloverWam_639221758879609174" order="1" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInPediatricTumors" xlink:label="clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInPediatricTumors_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInPediatricTumors_639221758879609174" order="2" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentDirectExpenseManufacturingAndRelatedCosts" xlink:label="clrb_ResearchAndDevelopmentDirectExpenseManufacturingAndRelatedCosts_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentDirectExpenseManufacturingAndRelatedCosts_639221758879609174" order="3" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInTripleNegativeBreastCancer" xlink:label="clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInTripleNegativeBreastCancer_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentDirectExpensePhase1StudyInTripleNegativeBreastCancer_639221758879609174" order="4" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentDirectExpensePhase3StudyInCloverWam" xlink:label="clrb_ResearchAndDevelopmentDirectExpensePhase3StudyInCloverWam_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentDirectExpensePhase3StudyInCloverWam_639221758879609174" order="5" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentIndirectExpensePreClinicalProjectsCosts" xlink:label="clrb_ResearchAndDevelopmentIndirectExpensePreClinicalProjectsCosts_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentIndirectExpensePreClinicalProjectsCosts_639221758879609174" order="6" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_ResearchAndDevelopmentIndirectExpenseGeneralResearchAndDevelopmentCosts" xlink:label="clrb_ResearchAndDevelopmentIndirectExpenseGeneralResearchAndDevelopmentCosts_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_ResearchAndDevelopmentIndirectExpenseGeneralResearchAndDevelopmentCosts_639221758879609174" order="7" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="clrb-20260630.xsd#clrb_GeneralAndAdministrativeExpenses" xlink:label="clrb_GeneralAndAdministrativeExpenses_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="clrb_GeneralAndAdministrativeExpenses_639221758879609174" order="8" use="optional" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingOtherItemAmount" xlink:label="us-gaap_SegmentReportingOtherItemAmount_639221758879609174" />
    <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_3" xlink:to="us-gaap_SegmentReportingOtherItemAmount_639221758879609174" order="9" use="optional" weight="-1" />
  </link:calculationLink>
</link:linkbase>
