A solid state chain extension method provides for the formation of a solid state film comprised of a high molecular weight polymer by chain extending a deblocked Lewis base with Lewis acid oligomers while the reactants are in a solid state form. In one embodiment, a negative resist is prepared by selectively exposing regions of the solid state film. The Lewis base is deblocked at the exposed regions by a suitable deblocking means. The Lewis acid oligomers and the deblocked Lewis base chain extend at the exposed regions. Development of the film removes the non-polymerized reactants. Optionally, the Lewis acid oligomers, when radiation-cross-linking, are cross-linked with one another prior to deblocking the Lewis base to form a negative resist. The cross-linked oligomers polymerize with the subsequently deblocked base to provide a high molecular weight polymer film. In an alternative embodiment, a positive resist is used by degrading and removing photo-sensitive Lewis acid oligomers using selective exposure lithography techniques and, subsequently, deblocking the Lewis base and chain extending the remaining oligomers with the deblocked Lewis base at the unexposed regions.