In this work we have shown that a random forest model can be used as a rapid screening tool to find thiophene-based oligomers with low and high λ. From the predictions of the model and the relative feature importance, it is clear that oligomers with large, conjugated π-systems have lower internal reorganization energies. In addition to a large π-system size, monomers with low steric bulk, which minimally change conformation upon a hole transfer, that also yield a high degree of delocalization and π orbital overlap between the monomers, also contributes to low λ. One monomer in particular, with a thiadiazole group, is frequently observed in compounds with low internal reorganization energy. Moreover, aromatic nitrogen substituents are frequently observed in such compounds. All the top oligomers also share similar geometries, i.e., being almost completely flat, and only exhibit minimal changes in geometry upon a hole transfer. Future work can consider a similar method for internal reorganiza- The monomer numbers, the predicted and calculated B3LYP λ, The GFN2 and B3LYP geometrical data of the average change in dihedral angles between the neutral and cation species, and average change in the inter-ring bond length of both neutral and cation species for the five hexamers with the lowest B3LYP λ.