Activity coefficients of 52 organic compounds in four ionic liquids (ILs), 1,3-dimedioxyimidazolium bis((trifluoromethyl)sullonyl)imide, 1-(methylethylether)-3-methylimidazolium bis((trifluoromethyl)sullonyl)imide, 1-ethano1-3-methylimidazolium bis((trifluoromethyl)-sullonyl)imide, and 1-(3-cyanopropyl)-3-methylimidazolium dicyanamide, were measured using inverse gas chromatography from (312 to 353) K. The retention data were also converted in gas-to-IL partition coefficients and water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the modified Abraham solvation parameter model. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.09 and 0.14) log units, respectively.