One of our motivations of implementing Mol2Vec and ESR approaches is that traditional measures of molecular similarity gave largely unsatisfactory results. In particular, similarity evaluated by the popular metrics such as Morgan-fingerprint-based Tanimoto coefficient (at the > 0.85 threshold ) made only rather trivial suggestions in which the parent and progeny shared a common scaffold with relatively small modifications in terms of functional groups (e.g., Cyclosporine parent and Volcosporin progeny differing in only vinyl vs. methyl groups; Ritonavir parent and its hydroxy-Ritonavir metabolite; Toremifene citrate and Tamoxifen differing in one chlorine atom). Unlike these traditional models -whose weaknesses are well documented -we have hoped to capture not only the "make-up" of the molecules in terms of the fragments they contain, but also information about the mutual arrangement (Mol2Vec) or even spatial, 3D distributions of the groups sharing similar properties though not necessarily the same atoms (e.g., in ESR, similar H-bonding/accepting propensities of structurally different groups).