The 1:2 molecular complexes of bis(N-alkyl-2-oxy-1-napthylideneaminato)copper(II) and -nickel(II) with 7,7, ́8,8 - ́tetracyanoquinodimethane (TCNQ) have been prepared and characterized, where N-alkyl group = CH3, C2H5, n-C3H7, iso-C3H7. The crystal structures of bis(N-isopropyl-2-oxy-naphthydeneaminato)copper(II) [I] and its 1:2 molecular complex with TCNQ [II] have been determined by the single-crystal X-ray diffraction method and refined by the block-diagonal least-squares method to give R = 3.55 and 3.71% for [I] and [II], respectively. The copper atom of compound [I] has a coordination geometry intermediate between square planar and tetrahedron, where the dihedral angle between CuNO planes is 38.6°. The crystal structure of compound [II] shows a typical π-π type molecular complex structure of alternately stacked donor (naphthalene moieties of metal complex) and acceptor (TCNQ) molecules where the copper atom assumes a square planar coordination geometry with a markedly stepped chair-like shape. ESR measurements have been revealed that the Å∥ values of the component copper(II) complexes are decresed and the g∥ values are increased in the order of increasing bulkiness of the alkyl groups. On the other hand, the Å∥ and g∥ values of the molecular complexes are less influenced by the bulkiness of the alkyl groups. The above results were discussed in relation to the coordination geometry around the copper atom. © 1979.