N,N-Bis(PEG2-alkyne)-N-amido-PEG2-thiol is a cleavable 4 unit PEG ADC linker used in the synthesis of antibody-drug conjugates (ADCs). N,N-Bis(PEG2-alkyne)-N-amido-PEG2-thiol is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.