N-(2,4-Dichloro)-salicylaldimine was synthesized, characterized by elemental analysis, FT-IR, and UV-visible spectroscopy, and its crystal structure was determined. The title compound is almost planar and contains short intramolecular O-H... N hydrogen bonds [O1-N1 2.601(1) Å]. It remains transparent in the visible region and has solvatochromic behavior in the UV region in the range 198 349 nm, implying non-zero microscopic first hyperpolarizability. The ab-initio quantum mechanical calculations (finite field second-order Møller Plesset perturbation theory) of the studied compound have been carried out to compute the electric dipole moment (μ) and the first hyperpolarizability (β) values. The ab-initio results also show that this ligand might have microscopic nonlinear optical behavior with non-zero values. © 2005 Verlag der Zeitschrift für Naturforschung, Tübingen.