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. The invention further relates to methods of producing combinatorial libraries of cyclic organic compounds from substrate bound compounds by cleaving the compounds from the support after synthesizing is completed and to assaying libraries of such compounds.