Disclosed is a coating comprising a polymeric layer, wherein the polymeric layer comprises a reaction product of a first monomer comprising two or more aromatic acetylene groups and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product. The coating may or may not additionally contain a crosslinker and/or a thermal acid generator. Optical thin films made from the coatings exhibit refractive indices that make them useful as interlayers for matching refractive indices between adjacent layers of display devices; thereby improving device output efficiency.