Benzyl-PEG8-azide is a PROTAC linker within the PEG category, used in the synthesis of PROTAC molecules. This compound serves as a click chemistry reagent, featuring an Azide group capable of Cu-catalyzed azide-alkyne cycloaddition reaction (CuAAC) with alkyne-containing molecules. Additionally, it can undergo a strain-promoted alkyne-azide cycloaddition reaction (SPAAC) with molecules containing DBCO or BCN groups.