The activity coefficient at infinite dilution, gamma(infinity) has been determined for 26 solutes (alkanes, alcohols, amines, aromatics, chloroalkanes, ketones, ethers) in a newly developed dicationic ionic liquid 1,9-di( N-naphthalen-2-ylmethylpyrrolidinium) nonanebis[(trifluoromethyl) sulfonyl] imide ([C9(2MNPTpy)(2)] [(NTf2)(2)]) by inverse gas chromatography at four different temperatures (T = 313, 323, 333 and 343 K). Solvation interactions between solvents and solute molecules have been estimated at T = (313, 343 and 373) K using Abraham solvation parameter. The experiments were carried out at various stationary phase loadings of (5 to 18)%. The selectivity values for cyclohexane/aromatics, octane/linear alcohols, octane/polar solutions were extracted from experimental activity coefficient data at T = 313 K. Compared with other ionic liquids from the literatures, this ionic liquid can be utilized as an efficient solvent for (aromatic + aliphatic) separation. (C) 2015 Published by Elsevier Ltd.