Benzenesulfonic anhydride is widely used as a sulfonating agent in organic synthesis, particularly for introducing sulfonyl groups into various compounds. It plays a key role in the production of dyes, pharmaceuticals, and agrochemicals, where sulfonation enhances solubility or reactivity. Additionally, it is employed in the synthesis of surfactants and detergents, improving their cleaning properties. In polymer chemistry, it is utilized to modify polymers, enhancing their thermal stability and chemical resistance. Its reactivity also makes it valuable in the preparation of intermediates for further chemical transformations.