This paper reports experimental vapor pressures of condensed phases of methyl p-cyano, p-formyl, p-nitro, and p-(methylamino) benzoates measured over the temperature ranges (303.9 to 393.0) K, (303.1 to 388.2) K, (319.0 to 415.8) K, and (332.9 to 392.4) K, respectively, using a static method based on capacitance diaphragm manometers. The Knudsen mass-loss effusion technique was also used to measure the vapor pressures of crystalline methyl p-(methylamino)benzoate in the temperature range (317.1 to 339.2)" K. These results enabled the calculation of the standard molar enthalpies and entropies of sublimation and of vaporization, at reference temperatures as well as the (p,T) values of the triple point of each compound. The temperatures and molar enthalpies of fusion were determined using differential scanning calorimetry and were compared with the values derived indirectly from the vapor pressure measurements. The enthalpies of the intermolecular hydrogen bonds O-H center dot center dot center dot O in the crystalline phase of the parent benzoic acids were determined.