A series of copper(II) salen complexes containing 4-substituted alkoxy chains of aromatic rings [Cu((4-CnH2n+1O)(2)salen)] (n = 3 (1), 4 (2), 6 (3), 8 (4), 10 (5), 12 (6), 14 (7), 16 (8), 18 (9), and 20 (10) and salen (N, N'-ethylenebis(salicylideneiminato)) has been prepared, and single-crystal structures of 2 center dot H2O, 4, and 6 by an X-ray crystallographic analysis have been revealed. Complexes 4 and 6 form tetrahedrally distorted square planer structure with one-dimensional polymeric stacking by van der Waals interaction between the dramatically distorted salen moieties. Complexes 1-3 did not exhibit any mesophases, but complexes 4-10 with longer alkoxy chains of n = 8-20 showed the metallomesogen of a lamello-columnar (ColL) mesophase in the smectic layers with the nearly constant stacking distances, irrespective of the variation of the alkoxy chain lengths by the X-ray diffraction measurements, which show similar behaviors to the corresponding Ni(II) complexes of n = 14-20. The molecular assemblies and mesomorphic properties in relation to the single-crystal structures of 4 and 6 with the liquid crystals at higher temperature are discussed.