Interactions of selected organic compounds with 16 functionalized based mono or dicationic ionic liquids were studied using inverse gas chromatography. Retention data were used to determine the selectivity and capacity values with these ionic liquids for four separation problems: hexane/benzene, hexane/methanol, hexane/thiophene, and cyclohexane/thiophene. It was found that the choice of the anion, the cation and the functionalized chain play an important role in the efficiency of the separation process. The solvation characteristics of this class of ionic liquids were also evaluated using linear solvation energy relationships (LSERs). Results indicate that mono and dicationic ionic liquids have similar solvation properties.