This work suggests that the standard donor-acceptor model is a relatively naïve one. The monomer acting as the HOMO donor is not necessarily the LUMO donor, which tends to complicate molecular orbital interactions upon combination. The diversity of molecular orbital interactions after dimer formation in this large dataset evidence the shortcomings of the donor-acceptor model. After dimer formation, some HOMO energy shifts were as high as 0.8 eV, suggesting a large delocalization of electron density. Most of the dimers in this data set exhibited an unexpected negative HOMO energy shift after dimer formation (2458 out of 4095 compounds). This observation is attributed to charge transfer interactions that result from large molecular dipole moments. When the Hückel model was applied to the compounds in this data set, the majority of the calculated 𝛽 values were complex numbers. is likely a reflection of the fact that the Hückel model does not account for charge transfer interactions. The complex 𝛽 values became much more prevalent when the differences between monomer HOMO and LUMO orbital energies were large, as evidenced in Figure . These large differences between monomer HOMO and LUMO orbital energies are also related to negative dimer HOMO and LUMO energy shifts and charge transfer interactions. The statistical models in this study performed relatively poorly until tetramer data were used to predict polymer FMO energies. Even using the calculated dimer FMO energies from the training set to calculate the polymer FMO energies, the mean absolute error for the HOMO/LUMO gap was on the order of 0.5 eV -the actual errors would likely be even higher. The inclusion of tetramer data drastically decreased the mean absolute error of the statistical models (HOMO/LUMO gap error of 0.16 eV for the training set, 0.22 eV for the test set). This error reduction after the inclusion of tetramer data likely follows from the emergence of a more accurate picture of oligomer conformational preferences. The conformation along the backbone of a polymer plays a significant role in the extent to which molecular orbital interactions can occur across conjugated systems. These conformational preferences are difficult, if not impossible, to predict using only monomer and dimer data.