Azido-PEG23-C2-azide is a PROTAC linker within the PEG class, utilized for the synthesis of PROTAC molecules. This compound acts as a click chemistry reagent, featuring azide groups that can undergo copper-catalyzed azide-alkyne cycloaddition reactions (CuAAc) with molecules containing alkyne groups. Additionally, it facilitates strain-promoted azide-alkyne cycloaddition (SPAAC) with molecules possessing DBCO or BCN groups.