Used as an intermediate in the synthesis of azo dyes and pigments, particularly for producing yellow and orange shades. It plays a key role in the textile industry for dyeing cotton, wool, and silk due to its ability to form stable color complexes. Also utilized in the manufacture of certain sulfa drugs and other pharmaceuticals where sulfonamide groups are required. Its chloro and sulfonic functional groups allow for further chemical modifications, making it valuable in organic synthesis and research.