The coupling of nucleophiles and aromatic rings is a key bond forming reaction used in the synthesis of drugs, agrochemicals and other functional materials (Scheme 1a). The use of transition metals, such as palladium, to mediate C-O and C-N bonds is now a well-established tool in drug discovery. Although SNAr, a metal-free reaction, is also routinely used to form such bonds, there are inherent mechanistic limitations to the scope of this reaction. The chemistry of hypervalent iodine is often described as "metal-like" and indeed the ligand coupling pathway for arylation with diaryliodonium salts bears a striking similarity to nucleophile-aryl reductive elimination from palladium(II) (Scheme 1a). Both the geometry and size of the central atom (Pd and I) are almost identical, though a key difference are the frontier orbitals that are used to bond to ligands and participate in the reductive elimination or ligand coupling mechanisms (Scheme 1a). The frontier orbitals of palladium were included in early mechanistic interpretations (ca. 1980) of reductive elimination. However, a re-analysis of the frontier orbitals on iodine have only recently been included in a comparison of ligand coupling from diarylhalonium salts, but not specifically in the context of the full mechanism of nucleophile arylation with diaryliodonium salts.