3,4-Diaminobenzenesulfonic acid 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, leather, and paper, providing vibrant and long-lasting hues. Additionally, it serves as a key component in the production of hair dyes, offering a range of shades and improved color stability. In the field of analytical chemistry, it is utilized as a reagent for detecting and quantifying specific metal ions due to its chelating properties. Its sulfonic acid group also makes it valuable in the manufacture of surfactants and detergents, enhancing their solubility and effectiveness in various cleaning applications.