The morphologies formed in poly[β-(N-carbazolyl)ethylacrylate-co-β-(metacryloyloxy) ethyl-3,5-dinitrobenzoate] [poiy(HECA-co-DNBM)] and in its triblock copolymer with poly(N-acetyliminoethylene) (pMeOZO) were investigated using transmission electron microscopy and differential scanning calorimetry (DSC) techniques. It was found that a lamellar structure was induced in the block copolymer even at a low content (⩽5%) of poly(N-acetyliminoethylene) as a consequence of the specific, dense, layered texture of the poly(HECA-co-DNBM) blocks, having an electron donor-acceptor complex character. The incorporation of poly(N-acetyliminoethylene) resulted in film quality improvement. The addition of small amounts of the block copolymer to the incompatible mixture of poly(HECA-co-DNBM) and pMeOZO having an appropriate composition leads to homogeneous blends able to form continuous films.