Coaxial nanocables compased of a uniform single-crystalline beta-SiC core, an amorphous SiO2 intermediate layer, and a graphitic carbon sheath (see Figure) have been synthesized via a simple chemical vapor deposition route. By annealing the nanocables, chains of carbon nanotube-SiC heterojunctions have been prepared. These nanostructures are suggested to be highly valuable as building blocks for nanoscale electronic devices.