N,N'-Dialkyl-(1,4-phenylene)bisimidazolium salts form inclusion complexes with cucurbit[7]uril (CB[7]) with high association constants. The stoichiometry or the complexes depends oil the alkyl chains and on the relative concentration of the imidazolium salt and CB[7]. The binding interactions of CB[7] with these bisimidazolium salts were studied experimentally by H-1 NMR, high resolution mass spectroscopy, and UV spectroscopy, and theoretically by semiempirical molecular modeling. Nonlinear regression analysis was used to calculate or estimate the binding parameters for the supramolecular inclusion complexes present in Solution. The detailed Study of the binding association of these imidazolium salts may allow us to understand the exact role of each recognition site in these salts and to assemble higher supramolecular complexes.