Used primarily as an intermediate in organic synthesis, particularly in the preparation of sulfonamide derivatives which are key structures in pharmaceuticals. It serves in the development of active pharmaceutical ingredients (APIs) due to its reactive sulfonyl chloride group, enabling coupling with amines to form sulfonamides. Commonly applied in the synthesis of anti-inflammatory, antimicrobial, and antidiabetic agents. Also utilized in the production of dyes and functionalized polymers where sulfonyl linkage is required. Its ester group allows further modification, making it valuable in multi-step synthetic routes.