Combinatorial synthesis is an automated process by which large numbers of novel structures are synthesized on a small scale using solid phase chemistry. A solid phase synthesis is carried out by linking the first molecule in the synthesis to the solid phase, then carrying out the rest of the synthesis on the polymer-bound structure. Therefore, in a parallel synthesis, each reaction vial contains a unique product and the structure of that compound will be known based on the reagents that were used. Parallel synthesis allows the rapid synthesis of a large number of analogs based on a common skeleton. Combinatorial synthesis is also used to deliberately synthesize a mixture of compounds in each vial. The synthesis of mixtures by combinatorial synthesis is carried out by a mix and split method. The mix and split method allows the synthesis of nine different dipeptides using three vials, compared with using nine vials in parallel synthesis.