Many of the early works on DTE photoswitches were dedicated to compounds based on the bisthienylcyclopentenyl core and its derivatives. Generally, these molecules exhibit high photocyclization yields depending on the chemical substitution, e.g., dithienylperfluorocyclopentenes. More recently, Herrmann showed that DTEs with cyclohexene in the backbone are similarly efficient. Interestingly, the cyclopentene and cyclohexene DTEs (1 and 2 in Figure ) present FMOs in agreement with our simple rules, i.e., with the proper symmetry and spatial localization (Figure ), as in T-CP-T (Figure ). Branda explored photoswitching of compounds with substituted cyclohexene rings linking the two side thiophenes (3 and 4), which exhibited good photocyclization ability. Our calculations identify both compounds as having FMOs in agreement with our orbital rules. On the other hand, a DTE with a 1,3-cyclohexadiene ring in 5 is not photoreactive, as predicted by the symmetry of the computed LUMO (Figure ).