Micrometer-sized carbon-cobalt spheres are demonstrated to be formed by the pyrolysis at 650 degrees C of a dicobalthexacarbonyl-complexed poly (p-phenyleneethynylene) derivative (see Figure). The spheres are obtained in quantitative yield and are shown to be composed of cobalt, carbon, and potentially a small amount of oxygen, rather than being all-carbon, as might have been expected.