The reaction of zirconium metallacycles is used to produce a variety of main group heterocycles including borole Diels-Alder dimers, galloles, indacyclopentadienes, siloles, germoles, stannoles, phospholes, arsoles, stiboles, bismoles, thiophenes, selenophenes, dihydrothiophenes, dihydroselenophenes, tetrahydrothiophenes, tetrahydroselenophenes, stannacyclopentanes, phospholenes, and isothiazoles. An X-ray crytallographic study of the borole Diels-Alder dimer of 1-phenyl-2,3,4,5-tetramethylborole is discussed and compared with the structure of 7-norbornenyl carbenium ions. The scope and potential for this metallacycle transfer reaction are delineated.