The standard (p = 0.1 MPa) molar enthalpy of formation of 6,7-dihydro-4(5H)-benzofuranone was measured, at T = 298.15 K, by static bomb calorimetry and the standard molar enthalpy of vaporization, at T = 298.15 K, was obtained using Calvet microcalorimetry. These values were combined together to derive the standard molar enthalpy of formation of the title compound in gaseous phase, at T = 298.15 K, -(226.0 +/- 2.8) kJ . mol (1). [GRAPHICS] Additionally, density functional theoretical calculations using the B3LYP hybrid exchange-correlation energy functional with extended basis sets and also other higher-level ab initio quantum calculations have been performed. (C) 2012 Elsevier Ltd. All rights reserved.