The standard (p(0)=0.1 MPa) molar enthalpies of formation Delta(f)H(m)(0)(I) at the temperature T=298.15 K were measured using combustion calorimetry for ethyl-2-phenyl-acetate, methyl-2-phenyl-propionate, and ethyl-2-phenyl-propionate. The standard molar enthalpies of vaporization of Delta(l)(g)H(m)(0) of these compounds were obtained from the temperature function of the vapour pressure measured in a flow system. Noticeable destabilized interactions of phenyl and alkoxycarbonyl substituents were derived from the enthalpies of formation in the gas phase of the compound under investigation. These values provide a further improvement to the group-contribution methodology for estimation of the thermodynamic properties of organic compounds