In this paper, a review about the role of Ionic Liquids on desulfurization of fuel oils has been done. From these salts, the pyridiniums are showing the most promising results on sulfur reduction by simple liquid-liquid extraction. For this reason, in this work the suitability of a new pyridinium ionic liquid as solvent in the extraction of sulfur- and nitrogen-containing compounds from fuels has been analysed. Liquid + liquid equilibrium data for 1-hexy1-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl] imide} + thiophene + n-hexane or n-dodecane or n-hexadecane and 1-hexy1-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl]imide} + pyridine + hexane ternary systems have been determined at 298.15 K and atmospheric pressure. High solubility of thiophene and pyridine in ionic liquid but also of toluene, has been found, being this salt practically inmiscible with linear hydrocarbons. Equilibrium data of these systems have been correlated with UNIQUAC and NRTL models driving to high deviations at high solute concentrations. Three steps extraction experiments with simulated gasoline and diesel and also with real samples, previous to refinery desulfurization process, confirmed ability of ionic liquid [hmmpy][Ntf(2)] as solvent for extractive desulfurization of transportation fuels. (C) 2010 Elsevier B.V. All rights reserved.