2-Azolyl-5-nitropyridines (the generic name “azoles” is hereafter used for pyrrole, diazoles, and triazoles, and “azolyls” for any substituents derivedfrom them) were examined from the viewpoints of the UV-vis absorption properties, the molecular hyperpolarizabilities (β), the second-harmonic generation (SHG) activities and the crystal structure compared with N-(4-nitrophenyl)azoles. In the azolyl-5-nitropyridines