The results presented herein highlight the potential of CDs as efficient catalysts for photoinduced SET processes and their remarkable compatibility with HAT-mediated C-H bond activation reactions. By systematically tuning their photoredox properties through compositional and surface engineering, CDs offer a versatile platform for precise catalytic activity modulation. This study establishes the feasibility for utilizing stable, Earth-abundant element based, CDs materials as photoredox catalysts, opening up vast opportunities for sustainable chemistry enabling previously inaccessible mechanisms and transformations. reaction. Angewandte Chemie International Edition, 60