Aniline-2,5-disulfonic Acid Monosodium Salt is widely used as an intermediate in the synthesis of dyes and pigments. It plays a critical role in the production of azo dyes, which are commonly applied in textiles, paper, and leather industries for vibrant and long-lasting colorations. Additionally, it is utilized in the manufacture of optical brighteners, enhancing the whiteness and brightness of various materials. Its sulfonic acid groups make it water-soluble, facilitating its use in aqueous dyeing processes. The compound is also employed in research and development for creating specialized chemical compounds with specific functional properties.