Used primarily as an intermediate in the synthesis of sulfonamide-based pharmaceuticals. It plays a key role in the development of antimicrobial agents, particularly in the production of sulfa drugs, which inhibit bacterial growth by interfering with folic acid synthesis. Its reactive sulfonyl chloride group allows for easy attachment to amines, making it valuable in constructing biologically active molecules. Also utilized in the preparation of dyes and functionalized polymers where controlled reactivity and stability are required.