Effective extraction of sulfur aromatic containing compounds from fuels by use of ionic liquids needs the knowledge and precise measurements of thermodynamic properties. In this work, effect of two types of the ionic liquids, 1-hexyl-3-methylimidazolium bromide [HMIM]Br, and 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM]EtSO4 on the thermodynamic properties of thiophene in hexane or cyclohexane solutions have been investigated. In this way, the densities, speeds of sound, and refractive indices of the solutions being studied have been measured at T = 298.15 K. These data have been used to calculate standard partial molar volumes V-phi(0), transfer partial molar volumes Delta V-tr(phi)0, partial molar isentropic compressibility kappa(0)(phi), and molar refractions R-D. The calculated parameters were used to discuss the manner of ionic liquid-thiophene interactions. Also, the scaled particle theory (SPT) was used to confirm and deep insight of results obtained from the calculated volumetric properties in terms of interaction volume V-int, and cavity volume V-cav. (C) 2015 Elsevier Ltd. All rights reserved.