N-Methyldiphenylamine is primarily used as an antioxidant and stabilizer in various industrial applications. It is commonly added to lubricants, greases, and hydraulic fluids to prevent oxidation and degradation, thereby extending the lifespan of these products. In the rubber and polymer industry, it acts as an antiozonant, protecting materials from ozone-induced cracking and aging. Additionally, it is utilized in the production of dyes and as an intermediate in organic synthesis, contributing to the development of various chemical compounds. Its stabilizing properties make it valuable in maintaining the performance and durability of materials exposed to harsh environmental conditions.