Boc-HyNic-PEG2-N3 is a PROTAC linker within the PEG class, suitable for synthesizing PROTAC molecules. It functions as a click chemistry reagent, featuring an azide group capable of undergoing copper-catalyzed azide-alkyne cycloaddition (CuAAc) reactions with molecules containing alkyne groups. Additionally, it can engage in strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules that have DBCO or BCN groups.