Used primarily as a fluorescent probe in biological and environmental applications due to its strong emission properties under UV light. It serves as a pH indicator in cellular imaging because its fluorescence intensity changes with protonation states. Commonly employed in microscopy and flow cytometry to track intracellular pH and monitor lysosomal activity. Also utilized in sensor systems for detecting metal ions and organic pollutants in water, thanks to its sensitivity to microenvironment changes. Its spirocyclic structure allows reversible responses to stimuli, making it suitable for smart materials and chemosensors.