Used as a key intermediate in the synthesis of fluorescent dyes, particularly in the production of rhodamine-based dyes. Its structure supports strong fluorescence and high photostability, making it valuable in biological staining, fluorescence microscopy, and labeling of biomolecules. Also applied in the development of sensors for detecting metal ions and pH changes due to its responsive optical properties. Additionally, it finds use in specialty inks and security dyes where detectable fluorescence is required.