Used primarily as an intermediate in the synthesis of pharmaceuticals and agrochemicals. Its sulfonyl chloride functional group allows it to participate in sulfa drug formation and other sulfonamide-based compounds, which are common in antimicrobial agents and herbicides. It is also employed in the preparation of specialty chemicals requiring chlorinated phenyl sulfonyl derivatives for further functionalization. Due to its reactivity, it is valuable in organic synthesis for building complex molecules where selective substitution on the aromatic ring is required.