3-Ethynylaniline is primarily used in organic synthesis, particularly in the development of pharmaceuticals and advanced materials. Its ethynyl group makes it a valuable building block for creating complex molecules through coupling reactions, such as Sonogashira coupling, which is widely used in medicinal chemistry to develop drug candidates. Additionally, it serves as a precursor in the synthesis of conductive polymers and organic semiconductors, which are essential in electronic devices like OLEDs and sensors. Its aromatic amine structure also allows it to be utilized in the production of dyes and pigments for industrial applications.