Au(iii)-aryl species have been unequivocally identified as reactive intermediates in oxidant-free C-O and C-N cross coupling catalysis. The crystal structures of cyclometalated neutral and cationic Au(iii) species are described and their key role in 2 electron-redox Au(i)/Au(iii) catalysis in C-O and C-N cross couplings is shown. Nucleophiles compatible with Au-catalyzed cross couplings include aromatic and aliphatic alcohols and amines, as well as water and amides

This work was supported by grants from the European Research Council (Starting Grant Project ERC-2011-StG-277801), Spanish MINECO (CTQ2013-43012-P to XR, CTQ2015-64436-P to TP, Consolider-Ingenio CSD2010-00065 and INNPLANTA project INP-2011-0059-PCT-420000-ACT1) and Generalitat de Catalunya (2014 SGR 862)