New isothermal binary vapor liquid equilibrium (VLE) systems of 1-pentanol + 2,2,4-trimethylpentane at 350.2, 360.2, and 370.2 K, methyl-tert-butyl-ether + 2,2,4-trimethylpentane at 307.2, 317.2, and 327.2 K, and methyl-tert-butyl-ether + 1-pentanol at 317.2 and 327.2 K were measured. The vapor-liquid equilibrium data were measured using a dynamic low pressure glass still. The experimental data were regressed using the gamma-Phi approach (combined method) with the Wilson, NRTL, and UNIQUAC activity coefficient models for description of the liquid phase nonideality. The virial equation of state with the Hayden and O'Connell correlation for the second virial coefficient was used to describe the vapor phase nonideality. The system of 2,2,4- trimethylpentane + 1-pentanol exhibited a minimum boiling azeotrope. The methyl-tertbutyl-ether + (2,2,4-trimethylpentane/1-pentanol) systems showed positive deviation from Raoult's law. The aforementioned activity coefficient models correlated the experimental data well. The thermodynamic consistency of the experimental data was determined using the point test of Van Ness and the Herrington area test.