In this study, the molecular structure and vibrational and electronic transition spectra and H-1 and C-13 NMR chemical shift values (gas phase and in chloroform solvent), HOMO-LUMO analysis, molecular electrostatic potential (MEP), thermodynamic properties and Mulliken atomic charges of (E)-344-(pentyloxy)phenyl]-1-phenylprop-2-en-1-one molecule, C20H22O2, which has many biological activities have been calculated using the DFT/B3LYP method with 6-311++G(d,p) basis set in the ground state. The obtained results indicate a good harmony among the calculated and the experimental FT-IR, Raman, UV vis. (in methanol solvent) and H-1 and C-13 NMR (in chloroform-d solvent) spectra of the mentioned compound. (C) 2014 Elsevier B.V. All rights reserved.