Azido-PEG2-C6-OH is a PROTAC linker belonging to the PEG family, utilized in the synthesis of PROTAC molecules. It is a click chemistry reagent containing an azide group, which can undergo a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules having an alkyne group. Additionally, it can participate in a strain-promoted alkyne-azide cycloaddition reaction (SPAAC) with molecules containing DBCO or BCN groups.