The bis(alkynyl) iridium complexes [Cp∗Ir(L)(CCAr)2] undergo an Arbuzov-type reaction with phosphites to give four-membered iridacyclic phosphonates [Cp∗Ir(L){C(Ar)=C[P(=O)(OR)2]C=CHAr}]. These can isomerise to a five-membered iridafuran in the presence of a strong acid. In the absence of a phosphite, the bis(alkynyl) iridium complexes undergo acid-catalysed aerobic oxidation to form 1,2-diketone iridabenzofurans [Cp∗Ir(L){C6H4-1,2-CH=CC(=O)C(=O)Ar}]. A common reaction pathway involving initial protonation and alkynyl migration is proposed. © 2016 Elsevier B.V.