The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-formyl-6-isopropylchromone (3F6I) were determined by combustion calorimetry. The molar combustion energies (Delta U-c(m)0 (cr, 298.15 K)) of the 3F, 3F6M and 3F6I are: -(4452.4 +/- 1.8), -(5115.6 +/- 2.7) and -(6411.4 +/- 2.5)kJ mol(-1), respectively. The formation enthalpies in the crystalline state (Delta H-f(m)degrees(cr, 298.15K)) are: -(340.2 +/- 2.2), -(355.1 +/- 3.1) and -(415.5 +/- 3.0) kJ mol(-1), respectively.s (c) 2006 Elsevier B.V. All rights reserved.