This review describes four methods for functionalizing vinyl polymers with photo-labile S2CNEt2 as ω-end groups．The normal atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) with a p-toluenesulfonyl chloride／Cu(S2CNEt2)／bpy initiation system was performed regardless of the original feed ratio of monomer／initiator

reaction temperature or solvent polarity. In conjunction with 2

2′-bipyridine (bpy)

Cu(S2CNEt2)catalyzed the BPO-initiated radical polymerization of MMA in bulk．The reverse ATRP of MMA and styrene (St) with the AIBN or BPO initiator could be successfully carried out in the presence of Cu(S2CNEt2)Cl／bpy complex．S2CNEt2 groups were demonstrated to ω- end-cap the obtained polymeric chains via the pseudo-halogen transfer reaction between the active and dormant species．Photo-polymerization of vinyl monomers under UV irradiation initiated by the resulting PMMA progressed at ambient temperature yielding extended PMMA and PMMA-b-PSt copolymers．Well-defined extended PMMA could be produced with the obtained PMMA and CuCl／bpy complex via the normal ATRP procedure.