The invention relates to an antireflective coating composition comprising a polymer, a crosslinker and a thermal acid generator, where the polymer comprises at least one unit of structure (1), at least one unit of structure (2) and at least one structure of structure (3), where R1 to R9 is independently selected from H and C1-C6 alkyl, R′ and R″ is independently selected from H and C1-C6 alkyl, X is C1-C6 alkylene, Y is C1-C6 alkylene. The invention further relates to a process for imaging a photoresist coated over the antireflective coating composition.