2-Methylphenylethyne, also known as 2-ethynyltoluene, is an aromatic alkyne compound. It serves as a versatile organic synthesis building block, particularly valued for its terminal alkyne group which enables various coupling reactions, such as Sonogashira, Glaser, and Click chemistry, to construct complex molecular architectures. Its primary application is in the field of materials science, specifically as a precursor for organic light-emitting diodes (OLEDs) and other organic electronic materials. The molecule can be incorporated into conjugated polymers or small-molecule semiconductors to tune their electronic properties, charge transport, and emission characteristics. The methyl substituent on the phenyl ring offers a handle for further functionalization and can influence the material's solubility and solid-state packing. This compound is a clear, colorless to pale yellow liquid. It requires careful handling due to its flammability and potential irritant properties. As a key intermediate, it is widely used in academic and industrial research for developing advanced optoelectronic materials.