2-Ethynyl-naphthalene is primarily utilized in organic synthesis as a building block for creating complex molecular structures. Its ethynyl group allows it to participate in various coupling reactions, such as Sonogashira coupling, which is essential in the development of pharmaceuticals, agrochemicals, and advanced materials. Additionally, it serves as a key intermediate in the synthesis of organic semiconductors and conjugated polymers, which are critical components in organic light-emitting diodes (OLEDs) and other electronic devices. Its unique structure also makes it valuable in the study of photophysical properties and the design of fluorescent probes for biological imaging.