Abstract: The invention relates to libraries of cyclic organic compounds and method of producing and assaying such libraries. According to the invention, each cyclic organic compound is constructed from a starting material in the form of a solid surface derivatized with a starting resin. Compounds are reacted with the resin to add or to form a cyclic group. The reactions are preferable carried out using a split resin procedure so that different compounds can be reacted with a plurality of subamounts so as to increase the size of the library. For example, compounds are reacted with a solid support bound starting resin to obtain a compound which includes an aldehyde functional group wherein the aldehyde compound or compounds reacted with it have substituents which are varied such that a mixture of products is obtained.