3,4-Diaminotoluene is primarily used as an intermediate in the synthesis of dyes and pigments. It plays a crucial role in the production of colorants for textiles, plastics, and inks, imparting vibrant and stable hues. Additionally, it is utilized in the manufacture of polyurethane foams and coatings, where it acts as a curing agent or crosslinker, enhancing durability and performance. In the field of organic synthesis, it serves as a building block for various chemical compounds, including pharmaceuticals and agrochemicals. Its applications also extend to the production of corrosion inhibitors and antioxidants, which are essential in protecting metals and extending the lifespan of industrial materials.