Electron Donor–Acceptor Complex Catalysis in Synthetic Chemistry

Electron donor-acceptor (EDA) complexes have become powerful platforms for light-driven radical synthesis. Although stoichiometric EDA photochemistry is now well established, its translation into catalysis is a more recent advance that requires charge-transfer excitation to be integrated with catalyst regeneration and productive turnover. This review focuses on the design principles that enable EDA complex catalysis, combining fundamental physical-organic concepts with mechanistic criteria for identifying productive catalytic manifolds. Current catalytic approaches are organized into donor-based, acceptor-based, and hybrid platforms, with emphasis on how transient catalytic species, medium effects, supramolecular organization, and confined environments facilitate EDA complex formation and expand the range of accessible synthetic transformations. By defining how photoactive donor-acceptor assemblies can be generated, activated, and regenerated within catalytic cycles, this review provides a framework for designing selective and synthetically useful light-driven catalytic radical processes.