Nanoporous materials are fabricated from polymers having backbones with reactive groups used in crosslinking. In one aspect of preferred methods and compositions, the reactive groups in the backbone comprise a diene and a dienophile. The diene may advantageously comprise a tetracyclone, and the dienophile may advantageously comprise an ethynyl. In another aspect of preferred methods and compositions, the reactive groups in the backbone are included in a conjugated system. Especially preferred polymeric strands comprise a poly(arylene ether) synthesized from a difluoroaromatic portion and an aromatic bisphenolic portion. It is still more preferred that the difluoroaromatic portions of the poly(arylene ether) are modified in such a way that some difluoroaromatic portions carry a thermolabile portion. In still other aspects crosslinking may advantageously occur without reliance on an exogenous crosslinker.