Excluding the 359 original ligands (35 exact and 324 substructure matches in KLIFS) and the 218 exact matches in ChEMBL (without KLIFS matches), the recombination generated 6,720,058 novel molecules out of 6,720,637 deduplicated recombined molecules, i.e. 99.99 % of chemical matter with no precedent in ChEMBL and in the 542 reduced original ligands in KLIFS. Furthermore, comparison of the recombined ligands with their most similar ChEMBL molecules revealed that the combinatorial library is not highly similar to the ChEMBL chemical space (mean similarity of 0.54 with a standard deviation of 0.07, see Figure ).