3-Nitrophenylacetylene is an organic compound featuring a phenyl ring substituted with both a nitro group and an ethynyl group. It is a yellow to orange crystalline solid with a molecular formula of C8H5NO2. This compound is a versatile building block in organic synthesis, primarily due to the reactivity of its terminal alkyne group, which can participate in Sonogashira coupling, click chemistry (copper-catalyzed azide-alkyne cycloaddition), and other cross-coupling reactions to construct more complex molecular architectures. Its primary application lies in materials science, particularly as a precursor for the synthesis of organic semiconductors and optoelectronic materials. The nitro group can be readily reduced to an amine, which is a common functional group in hole-transporting materials (HTMs) and electron-donating units. The ethynyl group allows for linear extension of π-conjugation, which is crucial for tuning the electronic properties, such as the HOMO-LUMO gap, charge carrier mobility, and absorption/emission characteristics of the resulting materials. It is used in the development of organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), and nonlinear optical materials. As a chemical intermediate, it must be handled with care. It is typically stored under inert atmosphere and at low temperatures to prevent polymerization or decomposition. Standard safety precautions for handling nitrated aromatic compounds and alkynes should be observed.