A Cu(II) complex with mixed ligands, [Cu-3(mal)(3)(phen)(3)(H2O)(2)] (.) 11H(2)O (mal = malonate, phen = 1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR, UV, electron paramagnetic resonance (EPR) and luminescence spectra and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group Cc with a = 13.1631(10) angstrom, b = 20.1089(10) angstrom, c = 20.1267(13) angstrom, beta = 103.500(3)degrees, V = 5180.2(6)angstrom(3), Z = 4, and R-1 = 0.0476 for 7993 observed reflections. In the complex, one Cu is coordinated by a mal dianion and a phen molecule, exhibiting N2O2 square-planar geometry, while the other two Cu atoms are coordinated, respectively, by a mal dianion, a phen and water molecules, exhibiting N2O3 square pyramidal coordination geometry.