6-Ethynylquinoline is primarily used in the field of organic synthesis and materials science. It serves as a versatile building block for the development of complex organic molecules, particularly in the synthesis of pharmaceuticals and agrochemicals. Its ethynyl group allows for efficient participation in click chemistry reactions, enabling the creation of diverse molecular architectures. Additionally, it is employed in the design of organic electronic materials, such as light-emitting diodes (OLEDs) and photovoltaic devices, due to its conjugated quinoline structure, which facilitates electron transport and light absorption. Its unique properties also make it a valuable component in the development of fluorescent probes and sensors for biological and chemical detection.