Newradical annulation reactions are described involving addition of cyano-substituted alkyl and sulfanyl radicals to aromatic isonitriles. The tandemcyclisation of the resulting imidoyl radicals onto the cyano group affords cyclopenta- and thienoquinoxalines, respectively. The intervention of the isonitriles in the aromatisation process of the cyclohexadienyl radicals is discussed, as well as the