The complex of univalent copper with α-(3, 3-dimethyl-3, 4-dihydroisoquinolyl-1)hydroxyiminoacetonitrile (LH) is synthesized and studied by X-ray diffraction and IR spectroscopy. As shown by X-ray diffraction analysis, structural crystal units are a binuclear complex consisting of two independent [Cu(LH)L] molecules joined by very strong hydrogen bonds O-H.O and an acetonitrile solvate molecule: [Cu(LH)L]2 · CH 3CN ( I ). The ligands coordinate the copper(I) atom at the vertices of a flattened tetrahedron in the bidentatechelating mode through their nitrogen atoms. The two independent ligands are linked to each copper atom, and one of the ligands exists in the molecular form LH, whereas the other exists in the form of the L ̄ anion. The Cu-N bond lengths range from 1.995 to 2.051 Å, and the NCuN angles are 80.7°-132.8° . All ligands exist in the same E-s-cis isomeric form. The IR spectroscopic characteristics of the complex are presented. © Pleiades Publishing, Inc., 2009.