Isobaric vaporliquid equilibrium (VLE) data for n-butanol + 1,4-butanediol and ?-butyrolactone + 1,4-butanediol have been experimentally determined by a improved Rose equilibrium still under pressures of 30.0, 50.0, and 70.0 kPa in this work. Additionally, the thermodynamic consistency tests of the experimental binary data were examined with the methods of the Herington area test and Van Ness point test, and then, three of the nonrandom activity coefficient models, which were two-liquid (NRTL), Wilson, as well as universal quasichemical (UNIQUAC), were selected to correlate the isobaric VLE data. All results demonstrated that the calculated values of the above-mentioned models achieved good agreement with the measured data.