Abstract: | Well‐defined azide polymers are successfully synthesized by visible‐light‐induced metal‐free electron transfer–atom transfer radical polymerization (PET‐ATRP) at room temperature. This technique uses Eosin Y/Et3N as the reductive quenching photocatalyst system, which can effectively prevent the destruction of the azide group in polymerization. Four kinds of azide‐derived monomers participate well in this reaction and obtain satisfactory results. The kinetic behavior, “ON/OFF” experiment, and chain‐extension experiment confirm the living feature of this visible light controlled polymerization. Moreover, random copolymers obtained by this protocol can be used as surface modifier which further demonstrates the utility and reliability of this method. |