AbstractIonic liquids (ILs) are alternative substances for post-combustion CO2 capture because of their tunable properties is reformed in terms cation and anion variance. The basicity and fluorination of either cation or anion of the ILs increases the CO2 sorption efficiency. In this study, four DBU based ILs namely [DBU][Ac], [DBU][TFA], [DBU][MSA] and [DBU][TFMSA] were used to study the CO2 solubility at various pressures and temperatures. The thermodynamic properties such as Henry’s constant (KH), enthalpy (ΔH) and entropy (ΔSo) were derived from experimental data. Among the four ILs [DBU][Ac] showed highest CO2 sorption efficiency (0.7992 mol/mol IL) than compare to other ILs and the order as follows: [DBU][Ac] > [DBU][TFAc] > [DBU][TFMSA] > [DBU][MSA]. Finally, FTIR analysis was performed to determine the CO2 sorption efficiency in ILs.