Towards NIR‐Active Hydroxybenzazole (HBX)‐Based ESIPT Motifs: A Recent Research Trend

Abstract In this review, we have explored the synthetic strategies adopted for designing the hydroxybenzazoles (imidazole, oxazole, and thiazole) i. e. HBX derivatives which show emission in red and NIR region. Further, we have examined the effect of different substituents i. e. either directly attached or with extended conjugation on a phenolic ring/ phenyl ring of heterocycles to achieve a red to NIR shift in emission. Finally, we have investigated the applications and computational methodologies adopted for red to NIR emitting dyes. In the future, this review will help to design, synthesized and examine the applications of new derivatives of HBX which will show emission in red to NIR region.