Microwave irradiation has been successfully applied in organic chemistry. Spectacular accelerations, higher yields under milder reaction conditions and higher product purities have all been reported. Indeed, a number of authors have described success in reactions that do not occur under conventional heating and modifications in selectivity (chemo-, regio- and stereoselectivity) have even been reported. Recent advances in microwave-assisted combinatorial chemistry include high-speed solid-phase and polymer-supported organic synthesis, rapid parallel synthesis of compound libraries, and library generation by automated sequential microwave irradiation. In addition, new instrumentation for high-throughput microwave-assisted synthesis continues to be developed at a steady pace. The impressive speed combined with the unmatched control over reaction parameters justifies the growing interest in this application of microwave heating. In this review we highlight our recent advances in this area, with a particular emphasis on cycloaddition reactions of heterocyclic compounds both with and without supports, applications in supramolecular chemistry and the reproducibility and scalability of organic reactions involving the use of microwave irradiation techniques.