Evidence for the transient formation of the heretofore unknown indole arynes is presented. Treatment of the 5,6-dichloro indole 1 with 4 equivalents of tert-butyllithium in ether at -78 °C leads to the formation of the 5- and 6-t-butylindoles 2 and 3 in good yield. Competition experiments with furan do not give the corresponding Diels-Alder cycloaddducts. A mechanistic rationale for these observations will be given.