In Fig. , we plot the enrichment and frequency of each substructure. This reveals a contravening trend: The simplest structure (1) is very common in the full dataset, but also displays very low enrichment in the lowλ set. In contrast, the more elaborate structures ( ) and ( ) are highly enriched, but very rare overall. Meanwhile substructure (5) (two meta-substituted acetylene-bridged benzene rings) features a quite high enrichment and is also fairly common in the database. As a consequence, ten further molecules with this motif can be found in the previously computed set of 10.900 λ DFT -values. This allows us to confirm that the corresponding molecules indeed display significantly lower reorganization energies than the full training set (Fig. ).