In this work the vapor pressure osmometry technique (VPO) has been used for the determination of osmotic and activity coefficients, at T = 323.15 K, of the binary mixtures containing 1-methyl-1-propylpiperidinium triflate ionic liquid, PMpipTFO, and alcohols, primary or secondary, 1-propanol, 2-propanol, 1-butanol, 2-butanol, or 1-pentanol. Using the vapor pressures experimentally obtained, the vapor pressure depressions were calculated. For the data correlation, the Extended Pitzer model of Archer (srd <= 0.015) and the MNRTL model (srd <= 0.044) have been adopted. Mean molal activity coefficients and the excess Gibbs free energy were obtained using parameters of the Extended Pitzer model of Archer. The results of this work were considered in terms of the (solute + solvent) and (ion + ion) interactions. (C) 2016 Elsevier Ltd. All rights reserved.