3-Ethynylbenzoic acid is primarily used as a building block in organic synthesis, particularly in the development of pharmaceuticals and fine chemicals. Its ethynyl group makes it a valuable intermediate for click chemistry reactions, such as the copper-catalyzed azide-alkyne cycloaddition (CuAAC), which is widely employed in drug discovery and bioconjugation. Additionally, it serves as a precursor in the synthesis of complex molecules, including polymers and advanced materials, due to its ability to form stable covalent bonds. In medicinal chemistry, it is utilized to create compounds with potential therapeutic properties, such as enzyme inhibitors or receptor modulators. Its versatility also extends to material science, where it contributes to the development of functionalized surfaces and nanostructures.