Ultralong‐Lived Excitons in Metallo‐Quinoline‐Incorporated Covalent Organic Frameworks Promote Photoreductive Cross‐Coupling

Abstract Designing long‐lived excitons in photocatalysts is crucial for efficient charge separation. However, most of the current organic photocatalysts are characterized by a relatively short exciton lifetime within the range of picoseconds due to localized excitons with large binding energies. Herein, we report the design of ultralong‐lived excitons with a lifetime exceeding 8000 ps by constructing metallo‐quinoline‐incorporated covalent organic frameworks (COFs). Post‐synthetic metalation into the quinoline‐containing skeletons of COFs allows the cooperative metal chelation at the COF interlayers to form monodispersed MN 2 O 2 species, ensuring the incorporation of metallo‐quinoline complexes into the COF structures at the molecular level. Diverse metal types are utilized to confirm the synthetic versatility, with the Fe(III)‐chelated one exhibiting the highest electrophilicity, distinctive orbital distribution, ultralong exciton lifetimes, and photostability. These features empower their use as efficient and robust heterogeneous photocatalysts for a challenging but desirable olefin‐carbonyl reductive cross‐coupling reaction, achieving remarkable conversion efficiencies and isolated yields for various substrates and good recyclability. This metallo‐quinoline complex‐incorporated strategy establishes a feasible way to elongate the lifetime of excitons in COF platforms for future photocatalytic research, which can cause a ripple effect for the metal‐incorporated COF field.