While we have strong structural and energetic arguments for our choice of the optimal MC model of Npe:TCNB, we must compare the computed UV-Vis absorption spectra to the experimental UV-Vis diffuse reflectance spectra, shown in Figure . Here we compare dips in the experimental reflectance spectra to calculated absorption peaks. The exact % R peak shapes will not be examined closely, as features such as >100% R values shown at low wavelength are likely due to fluorescence emission and outside the scope of this discussion. The calculated S1 state at 430 nm with oscillator strength f = 0.021 a.u. is characterized by a HOMO→LUMO transition, originating from intermolecular CT from Npe to TCNB, as shown in Figure . This transition corresponds to the experimentally observed dip around 450 nm (Figure b-c). The peak computed at 310 nm corresponds to the S4 excited state, f =0.478, seen experimentally at 350 nm. In contrast to the CT character of the S1 state, the S4 state exhibits local excitation within Npe, as seen in Figure . The theoretical S10 peak, f =0.356, computed at 250 nm (in excellent agreement with the experimental dip at 250 nm), is characterized by two orbital transitions, both with locally excited character, shown in Figure . The good agreement between the simulated spectrum of the cluster model and the experimental diffuse reflectance spectrum of the crystals supports our choice of the lowest-energy cluster model and aids in the characterization of the electronic structure involved in photon-induced CT.