The molar heat capacities (C-p) of guaiacol (CAS 90-50-1) and acetyl guaiacol ester (AGE, CAS 613-70-7) were determinated from 290 K to 350 K by differential scanning calorimetry (DSC), and expressed as a function of temperature. Two kinds of group contribution models were used to estimate the molar heat capacities of both guaiacol and AGE, the average relative deviation is less than 10%. The standard molar enthalpies of combustion of guaiacol and AGE were -3590.0 kJ . mol(-1) and -4522.1 kJ . mol(-1) by a precise thermal isolation Oxygen Bomb Calorimeter. The standard molar enthalpies of formation of guaiacol and AGE in a liquid state at 298.15 K were calculated to be -307.95 kJ . mol(-1) and -448.72 kJ . mol(-1), respectively, based on the standard molar enthalpies of combustion. The thermodynamic properties are useful for exploiting the new synthesis method, engineering design and industry production of AGE using guaiacol as a raw material. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.