The enamine (HEAID) obtained from aniline and 2-acetyl-1,3-indandione (2AID) behaves as a bidentate ligand in coordination with copper(II) ion. Two types of crystals, apparently different in shape, were isolated and studied by single-crystal X-ray diffraction. The X-ray data for the brown rhombic crystals of compound 1 shows a mononuclear complex of Cu(II) coordinated with two EAID(-) anions, Cu(EAID)(2). The X-ray data for the green crystals of compound 2 shows a dinuclear Cu(II) complex with two OH- groups acting as bridging ligands, [Cu-2(mu-OH)(2)(EAID)(2)]. In both cases the ligand coordinates after deprotonation of the amine group. (C) Central European Science Journals.