In continuing our investigations of control of excited state reactivity by inclusion in crystal lattices, we have encountered a variety of new examples of differing reactivity resulting from lattice restraints. Different theoretical treatments were tested and several proved applicable. Not only could the course of reactions imposed by the crystal lattice be predicted but also the ability to react versus lack of reactivity. For cyclohexenones with C-2 and C-5 substitution, either of two aryl groups at C-4 are available for migration; which one migrates depends on the lattice. One C-2 substituted and seven C-5 substituted cyclohexenones were investigated. Additionally some cyclopentenone photochemistry was investigated. Throughout, programming was developed to generate a "mini crystal lattice" having the appropriate space group symmetry and X-ray coordinates and with a central molecule surrounded by reactant molecules. Replacement of the central molecule with a transition state molecule provided a new "mini-lattice". Generally, the first diradical intermediate was used to simulate the reaction transition state. The mini-lattice was then subject to study. Overlap of the central, partially reacted species with the surrounding molecules provided one criterion. Molecular motion of the reactant excited state in forming the partially reacted species provided a test of least motion as a second criterion. A third test utilizing MM3 geometry optimization of the reacting species imbedded in the rigid mini-lattice, provided a measure of the increase in intra- and intermolecular energy of this molecule. A final approach determined the points of nearest molecule-lattice approach and mapped these in the form of a "lock and key"; this has the advantage of indicating which interactions result in inhibition or lack thereof of a particular reaction route. Predicting ability to react proved important since reactivity falls into three categories : (I) no reaction in the lattice, (2) differing reactivity compared to solution, (3) the same behavior in solution. Perturbing an intermediate geometry toward that of the reactant and then determining the deformation energy provided a reactivity measure.