Since the 1950s, diaryliodonium(III) salts have been demonstrated to participate in various arylation reactions, forming aryl-heteroatom and aryl-carbon bonds. Incorporating the arylation step into sequential transformations would provide access to complex molecules in short steps. This focus review summarizes the double functionalization of carbon-iodine(III) and ortho carbon-hydrogen bonds using diaryliodonium(III) salts. This involves arylation/intramolecular rearrangement, arylation followed by electrophilic aromatic substitution, three-component [2 + 2 + 2] cascade annulation, sequential metal-catalyzed arylations, and double functionalization via aryne formation.