Used in the synthesis of azo dyes and pigments due to its ability to form stable diazo compounds. Acts as an intermediate in producing colorants for textiles, leather, and paper. Also employed in the preparation of fluorescent whitening agents and optical brighteners for detergents and plastics. Its sulfonic acid group enhances water solubility, making it suitable for aqueous dyeing processes. Additionally, it finds use in analytical chemistry as a reagent for detecting certain metal ions.