Benzene sulfonyl chloride is widely used in organic synthesis as a reagent for introducing the sulfonyl group into various compounds. It is particularly valuable in the preparation of sulfonamides, which are important in the pharmaceutical industry for developing antibiotics and other therapeutic agents. Additionally, it serves as a key intermediate in the production of dyes, pigments, and agrochemicals. In peptide chemistry, it is employed for protecting amino groups during synthesis. Its reactivity with amines and alcohols also makes it useful in creating sulfonate esters, which are applied in polymer chemistry and as surfactants. Furthermore, benzene sulfonyl chloride is utilized in analytical chemistry for derivatization processes to enhance the detection of certain compounds in chromatographic analyses.