The activity coefficients at infinite dilution, gamma(infinity)(1,2), of 47 solutes including various (cyclo)alkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, aldehydes, and ketones, in the four ionic liquids (ILs) decyl(trimethyl)ammonium bis(trifluoromethylsulfonyl)imide, methyl(tributyl)ammonium bis(trifluoromethylsulfonyl)imide, octyl(trimethyl)ammonium bis(trifluoromethylsulfonyl)imide, and tetraoctylammonium bis(trifluoromethylsulfonyl) imide, were measured using inverse gas chromatography at temperatures from (323 to 343) K. The retention data were also converted to gas-to-IL 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 average standard deviations of 0.100 and 0.133 log units, respectively.