  Obtaining a robust superconducting state in atomically precise nanographene
(NG) structures by proximity to a superconductor could foster the discovery of
topological superconductivity in graphene. On-surface synthesis of such NGs has
been achieved on noble metals or metal oxides, however, it is still absent on
superconductors. Here, we present a synthetic method to induce
superconductivity to polymeric chains and NGs adsorbed on the superconducting
Nb(110) substrate covered by thin Ag films. Using atomic force microscopy at
low-temperature, we characterize the chemical structure of each sub-product
formed on the superconducting Ag layer. Scanning tunneling spectroscopy further
allows us to elucidate electronic properties of these nanostructures, which
consistently show a superconducting gap. We foresee our approach to become a
promising platform for exploring the interplay between carbon magnetism and
superconductivity at the fundamental level.
