Imidazolium based 1-butyl-3-methylimidazolium bromide [BMIM]Br has been synthesized and employed as energy efficient green solvent for desulfurization of liquid fuel. The FTIR, H-1 NMR and C-13 NMR have been discussed for the molecular confirmation of synthesized ionic liquid. The thermal analysis, conductivity, solubility, and viscosity analysis of ionic liquid were carried out. The effects of time, temperature, sulfur compounds, and recycling of ionic liquid without regeneration on dibenzothiophene removal from liquid fuel were studied. In extractive desulfurization process, the removal of dibenzothiophene in n-dodecane was 79.5% for mass ratio of 1:1 in 30 min at 30 degrees C under the mild conditions. Also, desulfurization of real fuels with ionic liquid and multistage extraction was studied. The results of this work provide meaningful insights in the understanding of imidazolium based [BMIM]Br for deep desulfurization of liquid fuels as it can be reused without regeneration with considerable extraction efficiency. Huge saving on energy can be achieved by use of imidazolium ionic liquid in process. (C) 2015 Elsevier B.V. All rights reserved.