Known isocyanide-based multicomponent reactions (IMCRs) are usually triggered by addition of the isocyano group to the strong electrophilic component. We herein report a new isocyanide-based three-component reaction, in which an unprecedented quinoxaline-based zwitterionic intermediate is generated from the chemoselective heterodimerization of weak electrophilic ortho-diisocyanoarenes and common isocyanides. This reactive zwitterion could react in situ with various trapping agents to furnish a range of structurally diverse quinoxalines.