In this manuscript the synthesis of four new ionic liquids (ILs) having the same cation (1,4-butane sultone methyl-benzimidazole) but different anions (CH3SO3�, CF3SO3�, CF3CO2�, HSO4�) were synthesized and characterized. The ILs was characterized using NMR, elemental analysis (CHNS) and FTIR. The physicochemical properties for these ILs, such as viscosity, density, refractive index, surface tension and thermal stability were analysed in a wide temperature window. Moreover the effects of different anions on the physicochemical properties were studied as well. The density and surface tension values were further used to calculate other properties such as thermal expansion coefficient, surface enthalpy, surface entropy as well as the boiling point and critical temperature of the ILs. The thermal stability analyses were performed from (373.15�773.15) K. © 2016 Elsevier B.V.