A composition suitable for use as a planarizing underlayer in a multilayer lithographic process is disclosed. The inventive composition comprises a polymer containing heterocyclic aromatic moieties. In another aspect, the composition further comprises an acid generator. In yet another aspect, the composition further comprises a crosslinker. The inventive compositions provide planarizing underlayers having outstanding optical, mechanical and etch selectivity properties. The present invention also encompasses lithographic structures containing the underlayers prepared from the compositions of the present invention, methods of making such lithographic structures, and methods of using such lithographic structures to pattern underlying material layers on a substrate.