The aim of this study is to investigate the possible use of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMM][OTf]) as solvent for three separation tasks which appear in deep desulfurization of fuels: {aromatic sulfur compound + aliphatic hydrocarbon}, {nitrogen compoud + aliphatic hydrocarbon}, or {sulfur compound + aliphatic hydrocarbon}. New three ternary systems are studied to investigated the capacity and selectivity of [BMIM][OTf] for extraction of sulfur and nitrogen containing aromatic organic compounds from aliphatic hydrocarbons. Aromatic hydrocarbon capture, which often appears causing unwanted reduction of fuel Octane number, is also investigated. Therefore, LLE measurements of ternary mixtures for three Systems are presented: {thiophene n-heptane + [BMIM][OTf]}, {pyridine + n-heptane [BMIM][OTf]}, {benzene + n-heptane + [BMIM] [OTf]}, and {thiophene + n-heptane [BMIM][OTf]} at 298.15 K and atmospheric pressure. The liquid-liquid equilibrium (LLE) data are correlated by the use of the NRTL model. Moreover, the extraction experiments of synthetic fuels-model gasoline and model diesel using [BMIM[OTf]-have been performed. The influence of three stepped extraction procedure using each time a fresh portion of [BMIM][OTf] on the final gasoline and diesel compositions is presented.