pseudosymmetric LUMO (Figure ). These results are confirmed by the Kohn-Sham energy orbital diagram of both molecules (Figure ). The same symmetry-based criteria can be applied to T-Ta-T and T-Tb-T molecules. While the former results in a swap of the HOMO/LUMO local symmetry properties with respect to the orbital diagram of hexatriene (Figure ), the disposition of the thiophene unit at the backbone in T-Tb-T recovers the proper orbital symmetry. Indeed, molecules based on the T-Tb-T structure have shown good photoreactivity, whereas, no derivative of T-Naph-T and T-Ta-T that undergoes photoinduced cyclization has been reported. Alternatively, it is also possible to promote photocyclization by stabilizing the C2 symmetric virtual orbital in T-Naph-T through chemical substitution. For instance, oxidation of the thienyl sulfur atoms to thiophene dioxide (TO2-Naph-TO2) removes the heteroatom pz orbitals from the p-system of T-Naph-T, reducing the antibonding interaction in the C2 symmetric LUMO+1 and stabilizing its energy with respect to the naphthalene (antisymmetric) LUMO (Figure ). Despite that this orbital stabilization is not enough to reverse the energy ordering of LUMO and LUMO+1, the energy gap between the two orbitals that could cause photocyclization, HOMO-1 and LUMO+1 in Figure