Vertical UV-Vis absorption properties of PPMet-1, PPMet-6, and PPMet-4 are summarized in Table ; for the plots of key Natural Transition Orbitals (NTOs) for the PPMet-4 system, check Figure , while the NTOs for the remaining transitions and other complexes can be found in Figs. S1-S3 in the ESI. The vertical electronic excitation properties, calculated up to the S 5 state, reveal several characteristic optical features of the PrdPyr-MeOH system. Firstly, in all cases the S 1 state is dark, of nπ * character, and is mostly localized on the PrdPyr molecule, with just a minor MeOH -→ PrdPyr charge transfer (CT) contribution noticeable for PPMet-4. Secondly, the absorbing state, S 2 , originates from a pure ππ * transition within the PrdPyr moiety. The S 2 state, separated from the S 1 state by almost 1.0 eV in the Franck-Condon region, is followed by a manifold of closer-lying states of mostly nπ * character and negligible oscillator strengths. Hence, in the low-energy excitation Table : UV-Vis absorption properties of PPMet-1, PPMet-6, and PPMet-4 at their S 0 -optimized structures, determined at the ADC(2)/cc-pVDZ level of theory: E -vertical excitation energy, f -oscillator strength, Character -transition character determined from NTOs calculated for each transition. The corresponding NTO plots can be found in Fig. regime, the photochemistry of the PrdPyr-MeOH system is expected to depend primarily on the S 2 and S 1 states' properties.