Project Summary. Catalysis has long been a potent force for advancing biomedical research by enabling the construction of biologically important molecules with ever-increasing speed, efficiency, and versatility. One of the most potent driving forces for progress in the area of catalysis has been the discovery of new catalytic platforms and concepts. The proposed research program is broadly focused on advancing the area of catalysis through the development of novel catalytic platforms, concepts, and methods. In particular, we have developed two generic catalytic strategies with broad applicability over a wide array of reaction types. In the first program, we have helped to pioneer the area of electrophotocatalysis, which combines the power of light and electrical energy within a single catalyst to promote challenging chemical reactions. Especially, we have introduced trisaminocyclopropenium (TAC) ions as a novel class of electrophotocatalyst; these catalysts have proven to be useful for a number of transformations, including C–H bond functionalizations and olefin derivatizations. The current application seeks to leverage electrophotocatalysis to realize other challenging, unprecedented reactions, especially those requiring very high redox potentials or involving multiple redox events. In the second program, we have pioneered the area of catalytic carbonyl-olefin metathesis, using hydrazine catalysis. This foundational capability enables a wide range of potentially advantageous synthetic methods. The current application seeks to make major advances to this program by designing highly reactive, next-generation catalysts that greatly expand the scope of substrates that can be engaged. We also aim to apply this mode of catalysis to useful new chemical methods, and to develop related catalytic platforms using these general principles. These and other investigations into the use of novel ideas in catalysis will continue to serve as a stimulus for advancements in chemical synthesis.