A method for the encoding of split/mix combinatorial chemical libraries based on Euclidean shapes is described. The shapes are fashioned from a polymeric matrix designed to swell in common organic solvents while retaining their unique forms, and exhibit good mechanical strength. The lightly crosslinked gel-type polymer was processed into an array of Euclidean forms that serve as encoding elements in the synthesis of combinatorial chemical libraries by using the split/pool methodology. To assess the viability of this approach, a library of compounds based on a urea scaffold was prepared. The validity of this methodology was demonstrated through correct deconvolution of the library mixture by shape discrimination. Furthermore, because the shapes used have a large surface area to volume ratio, each monolith can act as an independent chemical reactor. This simplifies the analytical identification process because each compound can be prepared in significant quantities and isolated as single entities. Given the high loading capacity of the monoliths and the conceptually simple encoding strategy, it is envisioned that these Euclidean forms will find significant application in combinatorial and high-throughput synthetic chemistry.