The present invention relates to a spin-on antireflective coating composition for a photoresist comprising a polymer, a crosslinking compound and a thermal acid generator, where the polymer comprises at least one functional moiety capable of increasing the refractive index of the antireflective coating composition to a value equal or greater than 1.8 at exposure radiation used for imaging the photoresist and a functional moiety capable of absorbing exposure radiation used for imaging the photoresist. The invention further relates to a process for imaging the antireflective coating of the present invention.