Photocatalytic CO 2 reduction using a diazabenzacenaphthenium photosensitizer and a Mn catalyst

reduction. These findings suggest that numerous candidates, with or without TADF properties, could serve as organic redox photosensitizers free of heavy metal ions. For optimal performance, such molecules should achieve as high a triplet excited-state formation yield as possible while keeping the singlet excited-state lifetime as short as possible.