Quantum chemical calculations of geometrical structure and vibrational wavenumbers of 8-hydroxyquinolinium picrate (8-HQP) were carried out by ab initio HF and density functional (DFT/B3LYP) method with 6-31++G(dp) basis set. The calculated geometric parameters of 8-HQP are presented. A detailed interpretation of the infrared spectra of 8-hydroxyquinolinium picrate (8-HQP) are also reported. Theoretical molecular frontier orbital energies of the title compound have been calculated using the method mentioned above in order to understand this phenomenon in the context of molecular orbital picture. The molecular HOMOs and LUMOs generated via HF and B3LYP method have been outlined. (C) 2011 Elsevier B.V. All rights reserved.