Rational design of metal-organic materials with needed architecture and properties is in focus of crystal engineers and materials scientists for about two decades. The ability of first-row transition metals to form complexes with ligands such as 1,10-phenanthroline (phen), 2,2’-bipyridine (2,2’bpy) or acetylacetonate (acac) is well known. The interest in copper complexes of phen and 2,2’bpy is stemming from their potential application as antimicrobial, antiviral, anti-inflammatory, antitumor agents, enzyme inhibitors, or chemical nucleases. From crystal engineering perspective the Cu(II) complexes containing chelating aromatic ligands are attractive candidates to design extended supramolecular architectures by π-π interactions involving metallocycles [1, 2]. Here, we report the crystal structures of five new Cu(II) complexes: three mononuclear [Cu(acac)(phen)(H2O)](BF4) (1), [Cu(acac)(phen)(dmf)](BF4) (2) and [[Cu(acac)(2,2’-bpy)(H2O)][ Cu(acac)(2,2’-bpy)]](BF4)2 (3), and two dinuclear dimers [Cu2(acac)2(2,2’-bpy)2(4,4’-bpy)](BF4)2 (4) and [Cu2(acac)2(2,2’-bpy)2(bpe)](BF4)2(H2O)2 (5) obtained by interaction of Cu(BF4)2·H2O with 2,2’-bpy (1) or phen (2) in the presence of Hacac and bridging rigid rod-like 4,4’-bipyridine (4,4’– bpy) or flexible 1,2-bis(4-pyridyl)ethane (bpe) exo-ligands. All structures reveal square pyramidal 4+1 copper(II) environment, where the equatorial planes are fixed by the acetylacetonate and chelate 2,2’-bpy or phen ligands. Axial position is occupied by oxygen atom in 1 - 3 and nitrogen atom in 4, 5. The replacement of axial ligand in mononuclear complexes by exo-bidentate bridging ligand results in dimeric binuclear complexes. The crystal structures of all compounds reveal π-π stacking interactions of basal planes of complexes involving metallocycles. It is interesting to note that the stacking interactions found in mononuclear complexes (Fig.1a) remain the similar in the structure of binuclear complexes (Fig.1b). Thus, our study prove the reliability of supramolecular synthon based on stacking interactions of square-planar Cu units with monoanionic acac and neutral N,N aromatic chelate ligands. The distances between the Cu(II) atoms within the supramolecular synthon based on stacking interactions are in the range 4.956-5.609 Å in the structures of mononuclear complexes and 5.825, 6.035 Å in binuclear complexes.