Fig. ) shows the distributions of number of heavy (non-hydrogen) atoms (NumHA), molecular weight (MW) and normalized spatial score (nSPS) for the three datasets as empirical cumulative distribution function plots (ECDF). nSPS is a recently introduced score to describe 3D (spatial) molecular complexity, taking into account hybridization, stereogenic centers, branching and ring membership of the constituting atoms. The score is generally normalized by the number of heavy atoms (nSPS) and consequently represents a complexity density. The distributions of the molecular weight show that approx. 80% of the full Enamine library and of the Enamine PNPs (Enamine-All and Enamine-PNP) have values below 400 g/mol.