Part of the integrated IBS SC collection is composed of the best of the Syntest Ltd., NELBI Ltd., ChemEx Inc., ExiMed Ltd. collections. Interbioscreen has purchased these selected sub-collections which are now Interbioscreen’s property. The synthetic library of IBS is built around functionalized heterocyclic drug-like molecules. Most of these cannot be obtained combinatorially. From the very start, IBS has been generating its library by making a very strict selection of the most interesting classes of compounds which have potential of becoming new drugs or plant protection agents or preparations for use in veterinary. We were less interested in simple hydrazones, hydrazides, Schiff’s bases or readily decomposing compounds. The major criterion for the inclusion of a compound in the collection has been the novelty, abundance in pharmacophores, diversity and the “drug-like molecule” structure.