In addition to this, benzothiazoles are widely used as fluorescent probes for analyte detection (Fig. ). Based on the mechanism of photoinduced electron transfer, excited-state intramolecular proton transfer (ESIPT), intramolecular charge transfer, aggregation-induced emission, the benzothiazole based fluorescent probes can specifically interact with the analyte (metal ions, anions, small molecules, biological macromolecules etc.), thereby changing their luminescence characteristics to achieve the detection of the analyte. Benzothiazole fluorescent probes can also be applied to the detection of harmful substances and cell imaging . Benzothiazole-based Ir(III) complexes are well-known as phosphorescent emitters in OLED devices .