Host–guest interactions in a new aza crown analog with alkali and alkaline earth metal ions are studied at different levels of theory. All the compounds are optimized at B3LYP/6-311+G(d) level of theory. To build the general idea about the consequence of methods of computation on the interaction energy of metal ions with the ligand, geometry optimization of some selected planar systems are carried out at the M05-2X, PBE0, wB97XD, and B3LYP-D levels. Calculated geometrical parameters, interaction energies, nucleus-independent chemical shift values, and thermodynamic properties highlight the selectivity associated with these interactions. Further insights into the nature of the bonding in these ion-macrocyclic supramolecular units are obtained through the natural bond orbital, atoms-in-molecules, bond energy decomposition, and electron localization function analyses. © 2014 Wiley Periodicals, Inc.