Sulfanilic acid is widely used in the dye industry as a key intermediate for producing azo dyes, which are essential for coloring textiles, paper, and leather. It also serves as a reagent in analytical chemistry, particularly in the Griess test, to detect and quantify nitrite ions in water and biological samples. In the pharmaceutical sector, it is utilized in the synthesis of certain drugs and sulfa antibiotics. Additionally, it finds application in the production of optical brighteners and as a corrosion inhibitor in industrial processes. Its versatility makes it valuable across various chemical and manufacturing industries.