Used as a key intermediate in the synthesis of high-performance fluorescent dyes, particularly in the development of near-infrared (NIR) fluorophores for bioimaging. Its spirocyclic structure enables pH-sensitive fluorescence switching, making it valuable in designing probes for cellular imaging and diagnostic assays. Commonly employed in the preparation of dyes for flow cytometry, immunoassays, and real-time imaging due to strong emission signals and photostability. Also utilized in optoelectronic applications, such as organic light-emitting diodes (OLEDs), where tunable emission and electron-deficient triflate group facilitate functionalization for material science uses.