Used primarily as an intermediate in organic synthesis, this compound plays a key role in the preparation of sulfa drugs and other pharmaceuticals. Its reactive sulfonyl chloride group allows it to form sulfonamides when reacted with amines, a critical step in creating antibiotics like sulfonamide-based antimicrobials. It is also employed in the synthesis of dyes, agrochemicals, and functional polymers due to its ability to introduce sulfonic acid derivatives into complex molecules. In research, it serves as a building block for modifying aromatic structures and developing new bioactive compounds.