We report covalently interchain-linked graphene nanoribbons fabricated on Au(111) by a stepwise growth process via two-zone chemical vapor deposition. Prepolymer arrays were grown by surface-assisted polymerization of a precursor, 1,9-dibromodibenzo[g,p]chrysene at 250 degrees C. Further annealing at 450 degrees C converted the prepolymers into interchain-linked graphene nanoribbons via intramolecular and intermolecular dehydrogenation reactions.