Homodesmic heats of reaction are computed at the B3PW91/6-31G* level as a means of determining gas phase heats of formation. These are then converted to solid state values by combining with Δ H sub, the latter being either experimental or calculated, with an empirical relationship based on molecular surface electrostatic potentials. Our focus, after evaluating the approach in four test cases, is upon six nitroaromatic compounds for which the literature Δ H f(solid) are ambiguous, i.e. two or more values have been reported that differ by at least 6 kcal/mol. The calculated results provide clear support for some of the experimental data at the expense of the remainder. This appears to be an effective approach to estimating Δ H f , provided that appropriately designed homodesmic reactions can be used.