Used primarily as an intermediate in organic synthesis, particularly in the pharmaceutical industry for the preparation of sulfonamide-based drugs. Its sulfonyl chloride group readily reacts with amines to form sulfonamides, which are key structural motifs in many medicinal compounds, including antibiotics and anti-inflammatory agents. Also employed in the development of agrochemicals and dyes due to its ability to introduce sulfonyl functionalities into aromatic systems. The ester group allows for further derivatization, making it a versatile building block in multi-step syntheses.