The growing demand for high-performance, fuel-efficient, and environmentally friendly internal combustion engines has led to research on fuel additives that enhance combustion efficiency and emissions control. n-Methylaniline (NMA)has gained attention as a potential octane booster in ethanol-gasoline blends, improving octane number, ignition timing, and knock resistance in spark-ignition engines. Studies show that NMA enhances combustion characteristics, thermal efficiency, and cold-start emissions, making it a promising option for sustainable fuel formulations. Additionally, it helps reduce NOx and CO2 emissions while maintaining fuel stability. However, concerns about its oxidation stability, toxicity, and long-term engine effects require further investigation. Comparisons with MTBE and ETBE highlight differences in degradation behavior and environmental impact, emphasizing the need for optimized formulations. Alternative ethanol and other additives blends have also shown potential in improving engine efficiency and reducing emissions. This review evaluates the feasibility of NMA as a superior octane enhancer, offering insights into its integration into modern fuel systems while balancing performance, durability, and sustainability.