Two　imine-based　covalent　organic　framework　photocatalysts　with　different　building　units,　TPB-DMTA-COF　and　TAT-DMTA-COF,　for　photo-induced　energy　transfer　reversible　complexation-mediated　radical　polymerization　(PET-RCMP)　were　developed　and　investigated,　producing　ideal　polymers　with　accurate　molecular　weight　and　moderate　dispersity　under　visible　light　irradiation.　The　chain　extension　and　spatiotemporal　control　experiments　revealed　the　high　chain-end　fidelity　of　polymers　and　the　compatibility　of　RCMP　processes　in　both　bulk　and　aqueous　system.　Moreover,　density　functional　theory　(DFT)　calculations　verified　that　heteroatom-doped　TAT-DMTA-COF　exhibits　higher　activities　for　weakening　C−I　bond　energy　barrier,　which　promotes　PET-RCMP　polymerization　performance.　This　work　demonstrates　that　rational　adjustment　of　building　block　for　constructing　COF　heterogeneous　photocatalyst　can　enhance　the　catalytic　performance　of　PET-RCMP,　providing　a　design　methodology　for　the　development　of　polymeric　organic　photoelectric　semiconductor　catalysts　to　mediate　RCMP.　©　2022　Wiley-VCH　GmbH.