Used as a key intermediate in the synthesis of acid dyes, particularly for wool, silk, and nylon textiles, providing bright fluorescent shades. Also employed in the formulation of optical brightening agents for detergents and paper due to its strong fluorescence under UV light. Its sulfonic acid groups enhance water solubility and affinity for polar substrates. Additionally, it serves as a fluorescent probe or labeling reagent in biochemical assays and analytical chemistry where detection sensitivity is critical.