According to a molecular dynamics study of benzene (C 6 H 6 ) and its derivatives C 6 F 6 , CH 3 -C 6 H 5 and CF 3 -C 6 H 5 in SC-CO 2 solution, the fluoro compounds are better solvated than the H analogs. This is supported by the analysis of average solute-solvent interaction energies and by free energy perturbation simulations at 305 and 350 K. Stepwise model building of C 6 X 6 (CO 2 ) n aggregates (X ¼ H and F) in the gas phase, however, indicates that up to n ¼ 6, interactions with CO 2 are stronger with benzene, while perfluorobenzene becomes better solvated at higher coordination numbers. Thus, the enhancement of the CO 2 -philicity upon fluorination does not stem from enhanced individual interactions with the CO 2 molecule, but from the higher coordination number, due to the increase of solvent accessible surface. Finally, simulations of C 6 H 6 and C 6 F 6 at the CO 2water interface reveal that the former is somewhat surface active due to specific O-HÁ Á Áp facial interactions between interfacial water molecules, while C 6 F 6 mostly sits in the CO 2 phase, in keeping with its larger CO 2 -philicity.