A novel Schiff base compound (Z)-1-[(2-Ethylphenylamino)methylene]naphthalene-2(1H)-one was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 2-ethylaniline. The structural properties of the compound have been characterized by using FT-IR, H-1 and C-13 NMR, UV-vis and X-ray single-crystal methods. According to X-ray diffraction result, the title compound exists in the keto-amine tautomeric form. The molecular geometry, vibrational frequencies, electronic absorption spectra and gauge including atomic orbital (GIAO) H-1 and C-13 NMR chemical shift values of the title compound in the ground state have been calculated by using density functional theory (DFT/B3LYP) method with 6-311G++(d,p) basis set, and compared with the experimental data. The obtained results indicate that optimized geometry can well reflect the crystal structural parameters. The theoretical values are in good agreement with the experimental ones. The energetic behavior of the compound in solvent media has been examined using B3LYP method with the 6-311G++(d,p) basis set by applying the polarizable continuum model (PCM). The total energy of the compound decreases with increasing polarity of the solvent. The molecular electrostatic potential (MEP), HOMO-LUMO energy gap and non-linear optical (NLO) properties of the compound were investigated using theoretical calculations. (C) 2015 Elsevier B.V. All rights reserved.