AbstractA number of cyclobutane derivatives containing one or more double bonds in endo‐ or exocyclic positions have been studied by the molecular mechanics method within the context of the MM2 force field. Generally speaking, the structures and energies of these compounds are well calculated in cases in which they are known experimentally and are predicted in others. Examples are shown of the use of the moments of inertia of molecules, which are known from microwave studies, in conjunction with molecular mechanics calculations to yield better structures than could be obtained by either method alone. Compounds examined include cyclobutene, methylenecyclobutane, Dewar benzene, and related compound