Used as an intermediate in the synthesis of dyes, pharmaceuticals, and agrochemicals due to its reactive sulfonic acid group and chlorine functionality. Its sulfonic acid moiety enhances water solubility, making it useful in the preparation of water-soluble compounds. Commonly employed in the production of sulfa drugs and other bioactive molecules where the chloro-substituted aromatic ring acts as a key structural element. Also utilized in polymer modification and as a catalyst or reagent in organic transformations requiring acidic conditions.