Metanilic Acid Sodium Salt is widely used in the dye and pigment industry as an intermediate for the synthesis of azo dyes. These dyes are essential for coloring textiles, paper, leather, and other materials, providing vibrant and long-lasting colors. Additionally, it serves as a coupling agent in the production of reactive dyes, which are known for their excellent wash-fastness and durability on fabrics. In the pharmaceutical industry, it is utilized as a raw material for the synthesis of certain drugs and active pharmaceutical ingredients (APIs). Its role in chemical research includes acting as a reagent for organic synthesis, particularly in reactions involving diazotization and coupling processes. Furthermore, it finds application in the manufacturing of optical brighteners, which are used to enhance the brightness of fabrics and plastics.