The key electric and UV-Vis absorption properties of PFCN are shown in Table on the example of the S R and M S forms. Firstly, one should notice a pronounced ground-state electric dipole moment of both isomers which is, to most extent, preserved upon excitation to the two lowest-energy singlet excited states, S 1 and S 2 . It should be also noted that, in both forms, the S 1 state is the bright state which can be reached with the UV light irradiation of about 3.75 eV (330 nm), and whose electronic configuration differs from a closed-shell ground-state configuration predominantly by the HOMO → LUMO electron excitation. On the contrary, the S 2 state, which requires excitation energy of roughly 4.20 eV (295 nm), shows dominant HOMO-1 → LUMO excitation character and negligible oscillator strength. Upon inspection of the relevant orbital plots shown in the SI (Section 1), it can be concluded that the S 1 state follows the typical pattern known for unsubstituted overcrowded-alkene motors, in which the lowest excited state is strongly delocalized, with clear ππ * character, and in which the initially double C=C bond between the rotor and the stator acquires a single-bond nature. The S 2 state, on the other hand, has a strong rotor-to-stator charge-transfer character, which is likely responsible for the low S 0 → S 2 absorption intensity. Above-discussed PFCN key ground-state and UV-Vis absorption features have been confirmed also at the ab initio level of theory: results of these calculations can be found in a dedicated Section 2 in the SI.