We describe a one-pot, simultaneous Suzuki-Miyaura cross-coupling of two different aryl boronic acids with symmetrical dibromo aryl and heterocyclic substrates to give as major products the unsymmetrical disubstituted tri(hetero)aryl derivatives. Yields of unsymmetrical dicoupled products were generally in the 52-75% range. This methodology is particularly suited to the generation of chemical libraries, as well as to the synthesis of biologically active or natural product analogs.