PBC DFT calculations were performed to quantify the effects of the extended solid on the structure of the D-A subunit in the crystal. Figure shows that the PBC DFT calculated structure is in good agreement with the experimentally observed structure with a centroid-centroid distance difference of 0.21 Å between experiment and PBC DFT. The main differences between the PBC and MC structures are: 1) the degree of rotation of TCNQ with respect to Npe and 2) the centroid-centroid distances. There is a larger degree of rotation observed in the MC structure, 60.5° compared to the experimental crystal structure, whereas the rotation in the PBC structure differs from the experimental crystal structure by 2.8°, consistent with the findings in the case of Npe:TCNB. Although a higher degree of rotation is observed in the MC structure, the centroid-centroid distance exhibits smaller deviation from the experimental crystal structure, 0.05 Å, than the distance deviation between the PBC DFT structure and experiment, 0.21 Å. Due to the larger differences between MC and crystal structure, we turn to comparing the theoretical and experimental UV-Vis spectra to validate MC model.