The invention is directed to a method of forming carbon nanomaterials or semiconductor nanomaterials. The method comprises providing a substrate and attaching a molecular precursor to the substrate. The molecular precursor includes a surface binding group for attachment to the substrate and a binding group for attachment of metal-containing species. The metal-containing species is selected from a metal cation, metal compound, or metal or metal-oxide nanoparticle to form a metallized molecular precursor. The metallized molecular precursor is then subjected to a heat treatment to provide a catalytic site from which the carbon nanomaterials or semiconductor nanomaterials form. The heating of the metallized molecular precursor is conducted under conditions suitable for chemical vapor deposition of the carbon nanomaterials or semiconductor nanomaterials.