In this contribution, modified UNIFAC (Dortmund) matrix for ionic liquids reported by Nebig and Gmehling [Fluid Phase Equilib. 302 (2011) 220-225] is extended. New parameters, determined on the basis of thermodynamic data extracted from literature, enable to apply the model to calculate various thermodynamic properties (limiting activity coefficients, liquid-liquid and solid-liquid equilibrium phase diagrams, and excess enthalpies) of binary systems formed by 1,1-dialkylpiperidinium ionic liquids based on bis[trifluoromethyl)sulfonyl]imide anion and different organic solvents (n-alkane, cycloalkane, 1-alkene, benzene, thiophene, 1-alcohol), or water. It is demonstrated that the modified UNIFAC (Dortmund) group contribution method is capable of capturing those different properties with a very good accuracy. (C) 2013 Elsevier B.V. All rights reserved.