A one-step, room temperature route to form carbon-metal bonds via spontaneous reduction of diazonium ion in an acid solution has been developed. This property was later employed to design a new process for self-activated electroless Co deposition on Cu without Pd activation. X-ray photoelectron spectroscopy and IR analysis show the evidence of direct organic molecule attachments on Cu. From scanning electron microscopy, electrical resistance, and line-to-line leakage current observations, the selectivity of Co deposition on the modified Cu surface has been greatly improved. Impedance measurements indicated that the charge transfer of electroless reaction was partially blocked by a highly covalent bond to the Cu surface. (c) 2007 The Electrochemical Society.