A mSA–mCS bipolar membrane was prepared by sodium alginate/polyvinyl alcohol (SA/PVA) and chitosan/polyvinyl alcohol (CS/PVA) modified by Fe3+ and glutaraldehyde as linking reagents, respectively. The mSA–mCS bipolar membrane was investigated by FT-IR, SEM, I–V curves, ion exchange capacity and changes of pH in the anode and cathode chambers. The SA–CS/PVA bipolar membrane was used as a separator in the electrolysis cell to electrogenerate 3-methyl-2-formylaminopyridine. The product yield was 49.8% and higher than that produced in a Nafion mono-membrane-equipped cell. Compared with the traditional chemistry method, the electro-generating process is moderate and eliminates pollution to the environment.