The synthesis of individual di- and tri-substituted-1,4-diazacyclic compounds having 6- to 8-atoms in the cyclic ring, their corresponding 1,6-diketo-2,5-diazacyclic compounds and similar 1,4-diazacyclic ring compounds having one ring carbonyl gorup and 6-8 atoms in the ring is disclosed, as are libraries of such compounds. Methods of preparing and using the libraries of compounds as well as individual compounds of the libraries are also disclosed.