2-Hydroxy-3-methoxy-N-(2-chloro-benzyl)-benzaldehyde-imine (C 15H14O2NCl) has been synthesized and then, characterized by elemental analysis, X-ray analysis, IR, 1H-NMR, and UV-Visible spectroscopies. The whole molecule is not planar. Each molecule contains a strong O-H⋯N hydrogen bond. To investigate the microscopic second-order nonlinear optical mechanism, the ab initio calculations of the electric dipole moments (μ) and the first hyperpolarizabilities (β) on model ligand have been performed using the FF MP2 method. The ab initio results reveal that the title compound has relatively good nonlinear optical properties. © 2004 Elsevier B.V. All rights reserved.