In this work, we explore the anion effect on the thermophysical properties of protic ionic liquids (PILs) such as triethylammonium acetate [Et3NH][CH3COO] (TEAA), triethylammonium dihydrogen phosphate [Et3NH][H2PO4] (TEAP) and triethylammonium hydrogen sulfate [Et3NH][HSO4] (TEAS) with polar solvent such as dimethylsulfoxide (DMSO). To understand the molecular interactions between DMSO with ILs, densities (rho), ultrasonic sound velocities (u) and viscosities (eta) have been measured over whole range of compositions and at three temperatures, 298.15, 303.15, and 308.15 K under atmospheric pressure. A second order empirical polynomial and Arrhenius equations were used to correlate the rho and eta as function of temperature, respectively. Sound velocity mixing rules were used on experimental values. Further, the excess molar volume (V-E), the deviation in isentropic compressibility (Delta kappa(s)) and deviation in viscosity (Delta eta) were calculated using these properties. The obtained V-E, Delta kappa(s) and Delta eta values were correlated by using the Redlich-Kister polynomial equation. (C) 2013 Elsevier B.V. All rights reserved.