4-Methoxydiphenylamine is primarily used as an intermediate in the synthesis of various organic compounds. It plays a significant role in the production of dyes, pigments, and other colorants, contributing to the vibrant and stable colors in textiles, inks, and coatings. Additionally, it is utilized in the development of antioxidants, which are essential in stabilizing materials such as rubber and plastics, preventing degradation caused by oxidation. Its application extends to the pharmaceutical industry, where it serves as a building block in the creation of certain drugs, particularly those targeting oxidative stress-related conditions. Furthermore, it is employed in research and development for studying chemical reactions and processes, aiding in the advancement of new materials and technologies.