We have fabricated a bilayer heterojunction solar cell consisting of p-n active layers of naphthalenetetracarboxylic bis-benzimidazole, N-CON, and zinc phthalocyanine, ZnPc. Conjugated naphthalene derivative of naphthalene bis-benzimidazole was employed as an electron acceptor. Bilayer solar cells were produced by successive evaporation of zinc phthalocyanine, ZnPc, and naphthalene bis-benzimidazole, N-CON, on glass substrates coated with indium doped tin oxide, ITO/PEDOT: PSS/ZnPc/N-CON/Al. Photovoltaic characteristics of bilayer cell were measured under simulated AM 1.5 sun illumination (V(oc) = 0.50 V, J(sc) = 2.11 mA/cm(2), FF = 0.51, g = 0.54%). Efficiency of the cell was discussed in relation to energy gap and work functions of the thin layers. (c) 2007 Elsevier B.V. All rights reserved.