Recent Progress in the Molecular Engineering of Excited-State Intramolecular Proton Transfer-Based...

This review provides a comprehensive summary of recent advances in excited-state intramolecular proton transfer (ESIPT)-based aggregation-induced emission luminogens (AIEgens), an emerging class of luminescent materials that effectively integrate the unique advantages of both ESIPT and aggregation-induced emission (AIE). Following a concise introduction, we have systematically examined the structural frameworks of ESIPT-active AIE systems, classifying them according to the nature of the ESIPT backbone and the strategies employed to incorporate AIE units. The synergistic combination of these two photophysical processes within a single molecular scaffold has led to the development of highly robust probes with exceptional sensitivity, selectivity, and photostability. Particular emphasis is placed on their applications in metal-ion recognition, anion detection, and biological sensing, with detailed discussion of the structure-property relationships that underpin their performance. Unlike earlier reports, this review uniquely focuses on systems where both ESIPT and AIE phenomena operate cooperatively to enhance sensing efficacy. Finally, we have outlined the key challenges that remain in this rapidly expanding field and discussed future opportunities. By capturing the exciting progress made so far, this review will serve as an authoritative reference and offer meaningful guidance for the design of next-generation ESIPT-AIE platforms with broader applications in chemical and biological sensing.