Abstract The experimental approaches coupled with computational methods are powerful tools to understand the physicochemical properties of ionic liquids. The 1,8-diazobicyclo[5.4.0]undec-7-ene-8-benzylium ([Bn-DBU]+) cation is a N-substituted DBU cation that was joined with various anions for production of [Bn-DBU][Y1-8], (Y1-8 = CH3CO2−, PhSO2−, PhSO3−, HCO3−, HSO4−, CF3CO2−, BF4−, and SCN−) ionic liquids (ILs). In this study, at first, several aprotic ionic liquids composed of [Bn-DBU]+ cation and various anions were synthesized and characterized experimentally by the combined of 1HNMR and FTIR spectroscopies, and thermogravimetric analysis (TGA). Then, density functional theory (DFT) at M06–2X/6–311++G(d,p) level of theory was used for calculation of the molecular electrostatic potential (MESP), interaction energies, structural parameters, vibrational frequencies, topological properties, charge transfer (CT) values and non-covalent interaction index.