Used as a key intermediate in the synthesis of pharmaceuticals, particularly in the development of sulfa drugs and other bioactive molecules. Its electrophilic sulfonyl chloride group readily reacts with amines and alcohols, making it valuable for introducing the 3-(trifluoromethyl)phenylsulfonyl moiety into target compounds. Widely applied in medicinal chemistry for constructing sulfonamide-based inhibitors, especially in agrochemicals and antitumor agents. Also employed in materials science for modifying polymer reactivity and enhancing thermal stability.