Used as an intermediate in the synthesis of biologically active compounds, particularly in pharmaceuticals and agrochemicals. Its sulfonic acid group enhances water solubility, making it valuable in designing molecules with improved bioavailability. Also employed in the preparation of functional dyes and fluorescent probes due to its stable isoindoline core, which supports conjugation in imaging applications. Additionally, it serves in polymer chemistry as a modifier to introduce ionic character into copolymers, enhancing their dispersibility and adhesion properties.