In this work, the 1,2,5-trimethylpyrrole was investigated by combining experimental (static bomb combustion calorimetry and high temperature Calvet microcalorimetry) and computational thermochemical (standard ab initio molecular calculations) results. The experimental value obtained for its standard (p degrees = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, Delta H-f degrees(m) (g) = (34.6 +/- 2.6) kJ center dot mol 1, at T = 298.15 K, is in excellent agreement with the estimated data obtained at the G3(MP2)//B3LYP level using a set of gas-phase working reactions. Thereby, these calculations were further extended to estimate the gas-phase enthalpies of formation of all the di-, tri-, tetra-and pentamethylpyrrole derivatives, whose experimental value is not known. Moreover, a new value for the gas-phase molar enthalpy of formation of 2,5-dimethylfuran, as -120.2 kJ center dot mol (1), determined with the G3(MP2)//B3LYP composite approach, is suggested. (C) 2014 Elsevier Ltd. All rights reserved.