Intermolecular interactions are responsible for most biochemical processes and often play crucial role in formation of structure and physical properties of molecular solids. Among them the π⋯π stacking interactions between metallacycles formed by aromatic ligands play an essential role for rational design of metal-organic materials with desired architecture. The contribution of these interactions in overall crystal packing is important for crystal engineering development. Figure 1. The HS over dnorm (a) and 2D fingerprint plots in 2 This work presents the results of the analysis of stacking interactions and their influence on the architecture of seven crystal structures of mono- and binuclear copper(II) complexes with composition [Cu(acac)(phen)(dmf)]BF4 (1), [Cu(acac)(phen)H2O]BF4 (2), Cu(acac)(phen)Cl]MeOH (3), [Cu2(acac)2(phen)2(4,4´-bpy)](BF4)2 (4), [Cu2(acac)2(2,2´-bpy)2(4,4´-bpy)](BF4)2 (5), [Cu2(acac)2(2,2´-bpy)2(bpe)](BF4)2(H2O)2 (6) and [Cu(acac)(2,2’-bpy)(H2O)][Cu(acac)(2,2’-bpy)](BF4)2 (7) [1], (acac=acetylacetonate, phen=phenanthroline, bpy= bipyridine, and bpe=1,2-bis(4-pyridyl)ethane). Hirshfeld surfaces (HS) analysis [2] and the calculation of energies interactions based on the program CrystalExplorer 17.5 [3] have been performed to study the contributions of different intermolecular interactions in crystalline packing of (1-7). The Hirshfeld surfaces were plotted in the range 0.4-2.4 Å for each of and di and de. The analysis of 2D fingerprint plots show that a major HS contribution of 13.6- 21.8% and 36,4-48.6% comes from two types of contacts, namely C···H and H···H, respectively. The contribution of C···C interactions largely correspond to π-π stacking interactions, which contribute to 1.9 - 6.2% of the Hirshfeld surfaces and appear on the fingerprint plots as a single triangle at about de = di ≈ 1,7 Å (Figure1). These interactions dominate in the packing of the structure of mentioned compounds. The intermolecular energy analysis calculated according to the energy model CE-B3LYP with 6-311G (d,p) basis set has revealed that the energy of π-π stacking interactions between the fragments involving metal chelate and the ligands fall in the range -41.1 – -80.9 kJ / mol and confirmed a significance of such interaction to the stabilization of supramolecular architecture. Figure 2. Interaction energy between neighboring molecules in the fragment of crystal packing in 2.