Organic Near‐Infrared Luminescent Materials Based on Excited State Intramolecular Proton Transfer Process†

Comprehensive Summary Organic near‐infrared (NIR) luminescent materials have captured intense research interest owing to their potential applications in optical communication, data storage, bioimaging, sensing and night vision. Excited state intramolecular proton transfer (ESIPT) process with absorption in normal form while emission in tautomer form can lead to a distinct redshift emission, based on which, a lot of organic NIR luminescent materials were designed. Because of attractive features such as ultrahigh sensitivity to the surroundings, large Stokes shift, and inherent four level system, ESIPT based NIR luminescent materials are supposed to be ideal fluorescent probes and gain materials. In this review, first, organic near‐infrared luminescent materials based on ESIPT process are summarized according to the core structures. Second, recent advances of ESIPT‐based organic near‐infrared fluorescent probes and organic NIR lasers are reviewed. Finally, the current challenges and prospects of ESIPT‐based organic NIR luminescent materials are introduced.