Gold(I)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes are described. This redox neutral strategy offers an efficient approach to diverse biaryls, vinyl arenes and arylacetylenes. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the in situ formation of Ph₃PAu^IR (R = aryl, vinyl and alkynyl) species which is crucial for the activation of aryldiazonium salts.