Supramolecular light-harvesting systems for organic photocatalytic transformations

Natural photosynthesis achieves exceptional solar-energy conversion through hierarchically organized light-harvesting antennae, directional excitation-energy migration, and spatially resolved reaction centers. Inspired by these principles, supramolecular chemistry provides a powerful platform for constructing artificial light-harvesting systems (LHSs) with tunable architectures, efficient Förster resonance energy transfer (FRET), and enhanced photocatalytic performance. In this Feature Article, we review recent advances in supramolecular LHSs for organic photocatalytic transformations, focusing on developments reported over the past three years. Representative systems are classified into two categories: (i) macrocyclic host-guest assemblies based on pillararenes, cucurbiturils, cyclodextrins, and emerging macrocycles, and (ii) assemblies constructed through other noncovalent interactions, including metal coordination, hydrophobic interactions, electrostatic interactions, and hydrogen bonding. Strategic donor-acceptor organization enables efficient FRET cascades, promoting excitation-energy funneling and reactive oxygen species generation for photocatalysis. We highlight key photophysical mechanisms and representative organic transformations, including oxidations, dehalogenation, and cross-dehydrogenative coupling reactions. Finally, we discuss current challenges and outline future directions toward adaptive and multifunctional supramolecular LHSs for organic photocatalysis.