Aniline-2,5-disulfonic acid is primarily used as an intermediate in the synthesis of dyes and pigments. It plays a crucial role in the production of azo dyes, which are widely utilized in the textile industry for coloring fabrics. The compound’s sulfonic acid groups enhance its solubility in water, making it suitable for dye formulations. Additionally, it is employed in the manufacture of optical brighteners and certain pharmaceutical compounds. Its ability to form stable complexes with metals also makes it useful in analytical chemistry for metal ion detection and separation processes.