Used as a key intermediate in the synthesis of fluorescein derivatives, particularly in the preparation of fluorescent dyes for bioimaging and labeling applications. Its hydroxyl and carboxylic acid functional groups allow for easy conjugation with biomolecules such as antibodies, peptides, or nucleic acids, making it valuable in immunoassays, flow cytometry, and fluorescence microscopy. The compound’s fluorogenic properties enable detection in biological systems with high sensitivity and low background interference. It is also employed in the development of sensors for pH, metal ions, and enzymatic activity due to its environment-sensitive fluorescence.