N-Ethyl-o-toluidine, a multifunctional dye, is crucial for biological experiments, aiding in the observation and analysis of cell structures, tracking biomolecules, evaluating cell functions, distinguishing cell types, detecting biomolecules, studying tissue pathology, and monitoring microorganisms. Its applications extend from basic scientific research to a wide range of clinical diagnostics. Additionally, dyes are extensively utilized in traditional areas like textile dyeing, as well as in emerging fields such as functional textile processing, food pigments, and dye-sensitized solar cells.