Used primarily as an intermediate in organic synthesis, especially in the preparation of pharmaceuticals and agrochemicals. It reacts with amines to form sulfonamides, which are key structural motifs in many biologically active compounds. Commonly employed in the development of drugs targeting central nervous system disorders and anti-inflammatory agents. Also utilized in the synthesis of dyes and functional materials where sulfonyl group introduction is required. Its reactivity allows for selective derivatization in multi-step synthetic routes.