4-Fluoro-3-methylbenzene-1,2-diamine hydrochloride is primarily utilized as a key intermediate in the synthesis of pharmaceutical compounds, particularly in the development of bioactive molecules such as anti-cancer agents and antiviral drugs. It acts as a building block for active pharmaceutical ingredients in medications targeting various therapeutic areas. Additionally, it plays a significant role in chemical research, facilitating the study of reaction mechanisms and the exploration of novel synthetic pathways for advanced materials and drug candidates.