The present study attempts to screen a number of ionic liquids (ILs) for CO2 capture and its separation from flue gas mixture based on Hildebrand solubility parameter (delta). Solubility parameters of various ILs have been computed through molecular dynamic simulations in Material Studio. Initially the density and solubility parameters of seven ILs have been validated with experimental values available in the literature and are found to be in close correspondence. A group contribution correlation for delta of IL is developed and expressed as the weighted sum of attractions and repulsions of cation and anion as: delta(2)(IL) = 0.6 delta(ca)delta(an) - 0.2 delta(2)(ca) - 0.2 delta(2)(an). This correlation was used to find out the delta values of cation and anion. The solubility parameters of 21 cations and 10 anions have successfully been determined by using delta values of 31 ILs and the correlation. Furthermore, using delta values of 21 cations and 10 anions and the group contribution correlation, the delta values of 210 ILs have been predicted. The delta values obtained by correlation match well with the delta values obtained by direct molecular simulations for twenty seven ILs, suggesting that correlation equation is reliable to predict the delta values of several ILs. Furthermore, comparison of the literature solubility data of different gases in ILs with that of solubility parameters in the present study reveals that the delta values are able to successfully explain the experimental solubility trends. Of all ILs studied, delta values of phosphonium cation based ILs (delta = 20.7-18.3 MPa0.5) and ILs containing tris(nonafluorobutyl)trifluorophosphate ([bFAP](-)) anion (delta = 20.5-18.3 MPa0.5) are observed to be closer to that of CO2 (delta = 17.85 MPa0.5) and are significantly far from that of other flue gases like CH4, N-2, H-2 and H2O. Thus, by using the fluorinated anion and phosphonium cation based ILs, CO2 can be more selectively separated from the major flue gases. (C) 2012 Elsevier B.V. All rights reserved.