5-Ethynyl-2'-deoxyuridine-13C2 (EdU-13C2) is a 13C-labeled version of 5-Ethynyl-2'-deoxyuridine. As a thymidine analog, 5-Ethynyl-2'-deoxyuridine (EdU) can be incorporated into replicating DNA molecules during cell proliferation. The conjugation reaction between EdU and a dye allows for efficient and rapid cell proliferation analysis. This compound also serves as a PROTAC linker, classified under alkyl chain types, and is used in the synthesis of PROTAC molecules. Additionally, 5-Ethynyl-2'-deoxyuridine functions as a click chemistry reagent, containing an alkyne group that can undergo a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) with molecules that have an azide group.