Hydroxythiophene-Conjugated Benzothiazole Derivatives: Photophysical Design and Applications in Imaging and Optoelectronic Materials and Devices

Abstract Benzothiazole derivatives are excellent molecular platforms for developing functional fluorescent probes, owing to their robust π-conjugated framework, chemical tunability, and excellent photostability. Benzothiazoles have a heteroaromatic structure with balanced rigidity and flexibility, enabling the fine modulation of electronic transitions through mechanisms such as intramolecular charge transfer and excited-state proton transfer. These photophysical characteristics provide high-performance fluorophores with environment-sensitive, wavelength-tunable, and reversible emission properties. In this account, we summarize recent advances in the design, photophysical principles, and applications of benzothiazole-based fluorescent probes, with emphasis on three representative systems developed in our research. These systems include (1) chemical sensing and environmental monitoring, (2) bio-application for subcellular imaging and pathogen detection, and (3) electrofluorochromic devices and hydrogels as optoelectronic materials. These examples demonstrate how the structural modularity of benzothiazoles can be exploited to introduce functional groups for bioimaging, chemical sensing, and optoelectronic applications.