The ECLiPS technology is a viable and effective method for producing and utilizing encoded combinatorial libraries. It allows the facile recording of the synthetic history of each bead in the library and the subsequent rapid and reliable identification of any active ligands. The ease and generality of ECLiPS combine to make this a powerful tool for both identifying novel lead compounds and performing rapid SAR studies. Work is also in progress at Pharmacopeia to expand the repertoire of organic reactions compatible with solid phase synthesis (38), and to develop new linking strategies for ligand attachment. These are both necessary to enhance synthetic flexibility and facilitate the design of future novel libraries.