Used as a key intermediate in the synthesis of cyanine dyes, which are widely applied in photographic sensitizers and infrared dyes. Also serves as a catalyst or reagent in organic transformations, particularly in the development of fluorescent probes and bioimaging agents. Its strong electron-donating properties make it valuable in the preparation of electroactive materials for optoelectronic devices. Additionally, it finds use in analytical chemistry for the detection of specific anions due to its colorimetric response.