Organocatalytic　atom　transfer　radical　polymerization　(O-ATRP)　is　recently　emerging　as　an　appealing　method　for　the　synthesis　of　metal-free　polymer　materials　with　well-defined　microstructures　and　architectures.　However,　the　development　of　highly　effective　catalysts　that　can　be　employed　at　a　practical　low　loading　are　still　a　challenging　task.　Herein,　we　introduce　a　catalyst　design　logic　based　on　heteroatom-doping　of　polycyclic　arenes,　which　leads　to　the　discovery　of　oxygen-doped　anthanthrene　(ODA)　as　highly　effective　organic　photoredox　catalysts　for　O-ATRP.　In　comparison　with　known　organocatalysts,　ODAs　feature　strong　visible-light　absorption　together　with　high　molar　extinction　coefficient　(epsilon(455nm)　up　to　23,950M(-1)cm(-1)),　which　allow　for　the　establishment　of　a　controlled　polymerization　under　sunlight　at　low　ppm　levels　of　catalyst　loading.　Organocatalytic　atom　transfer　radical　polymerization　(O-ATRP)　is　attractive　due　to　its　metal-free　nature　but　catalysts　are　rarely　applied　at　a　low　loading.　Here　the　authors　introduce　a　catalyst　design　logic　based　on　heteroatom-doping　of　polycyclic　arenes,　which　led　to　the　discovery　of　oxygen-doped　anthanthrene　as　an　organic　photoredox　catalysts　for　O-ATRP.