Although our predictions are consistent with experimental results from the literature, there are some exceptions that merit deeper analysis. As we have already discussed, the LUMO of TPh-CP-TPh and TNPh-CP-TNPh is not suitable for photocyclization, however, both of these compounds photoswitch. This discrepancy between calculations and experimental results can be rationalized by realizing that, in both of these compounds, the LUMO+2 is the orbital suitable for photocyclization, corresponding to the π*-type interaction of the cyclopentene double bond (Figure ). In both molecules, the first excited singlet state, S1, corresponds to the HOMO®LUMO transition, while the S3 state, which is far more optically active than S1 (larger oscillator strength), corresponds to the HOMO®LUMO+2 transition. In the experimental work, the excitation energy of the open form lies within the intense band corresponding to the S3 state, therefore, photoexcitation in these experiments populates the state allowing the formation of the closed photoproduct. On the other hand, internal conversion (IC) from the photoactivated S3 to lower lying excited states might compete with photocyclization, reducing the reaction quantum yield.