Excess molar enthalpies, excess molar volumes, and vapour pressures of {x(trans-CHCl:CHCl) + (1-x)(CH2ClCH2Cl or CCl2:CC(l)2 or CHCl2CHCl2)}, {xCH(2)ClCH(2)Cl + (1-x)(CCl2:CCl2 or CHCl(2)CHCl2)}, and {xCCl(2):CCl2 + (1 - x)CHCl2CHCl2} were measured at the temperature 298.15 K. Activity coefficients and excess molar Gibbs free energies were fitted to a polynomial by Barker’s method. For {xCH(2)ClCH(2)Cl + (1 - x)CHCl2CHCl2} all excess functions are negative and we believe that a 1-1 complex is formed as in the solid state.