Reliable bond dissociation energies (BDE) of various allylic compounds were obtained using compound methods. It was found that the C—H and Si—H BDE data display poor Hammett relationships, whereas the N—H, O—H, P—H and S—H BDE ones exhibit good Hammett relationships. It was also found that the resonance effect was more important than the inductive/field effect on the allylic BDE. In addition, the ground state and radical state effects on BDE were analyzed. All the results in the present study are in good agreement with our recent results about the benzylic BDE.

Key words: G3, CBS-Q, substituent effect, bond dissociation energy