Fig. shows a decreasing behaviour of HOMO-LUMO gap for oligoethylene and oligoacetylene as a function of the number of monomers n, in agreement with previous works as well as qualitative predictions from the Hückel model . Indeed, we have found that the absence of a qualitative change to the electronic structure within the ethylene oligomers leads to a relatively small HOMO-LUMO gap change going from n = 1 → 7 (≈1.5 eV) compared to the acetylene oligomers, where every monomer modifies the conjugation, producing a more significant change of ≈5.0 eV. Unlike HOMO-LUMO gap, the behavior of polarizability in the molecular chains can not be simply explained. The observation that polarizability monotonously increases with n is in line with both the principles of atomic additive models and the correlation with molecular size. However, the absolute magnitude of the polarizability values is significantly different for the two sets of oligomers, and this difference increments with increasing the number of monomers. This quantitative difference can neither be explained by atomic additive models nor correlations using molecular size, but it correlates with the reductions in HOMO-LUMO gap. Notably, not even AlphaML 31 can predict this behavior: the model predicts 181 a.u. for oligoethylene and 227 a.u. for oligoacethylene in the n = 7 case, with the DFPT results being 177 a.u. and 360 a.u., respectively. The difference due to conjugation is therefore underestimated by a factor of four even when using ML methods, and this error is expected to increase with increasing the chain length. Up to now, we are not aware of any other simple polarizability estimation method that can accurately predict the values in Fig. . These findings provide clear evidence that further work is necessary to enhance our understanding and improve and accuracy of computational methods used for calculating polarizability, even for relatively simple molecules such as hydrocarbon oligomers.