To improve water solubility of 1-butyl-3-vinylimidazolium bis(trifluoromethylsulfonyl)imide ([bvim]-[Tf2N]) the complexation with beta-Cyclodextrin (beta-CD) was carried out. Investigations of conductivity measurements, NMR and microcalorimetry show that beta-CD forms exclusively host-guest complexes with the anion bis(trifluoromethylsulfonyl)imide (Tf2N-). The received spatially separated ion pairs create quasi "naked" vinylimidazolium cations which do not polymerize in water by radical mechanism. Only in the presence of foreign salt is the cation-cation repulsion compensated and polymerization occurs.