Using ab initio calculations, cooperative effects between aerogen-bonding and anion-π or lone pair-π interaction is studied in some model complexes. A detailed analysis of the structure, interaction energy and bonding properties is performed on these systems. The results show that the strength of the aerogen-bonding interaction increases in the presence of an anion-π or a lone pair-π interaction. The estimated cooperative energies are between -0.27 and -11.96 kcal/mol. It is found that the effect of an anion-π interaction on an aerogen-bonding is more important than that of a lone pair-π. The strengthening of the aerogen-bonding in the multi-component complexes depend considerably on the strength of the anion-π or lone pair-π interaction and it becomes larger in the order X-= F- > Cl- > Br- and HX= HBr > HCl > HF.
