As a novel method for stabilization of bilayer membranes, coordinative polymerization of bilayer membranes of an amphiphile containing two ligating sites has been developed. Complexation of Fe(II), Fe(III), Co(II), or Co(III) ion with the bilayer membranes of amphiphile 3 which contains an o,o’-dihydroxyazobenzene moiety as the rigid segment leads to the formation of coordinatively polymerized bilayer membranes. The coordinatively polymerized bilayer membranes are characterized by transmission electron microscopy, gel filtration, phase transition, release of entrapped 5(6)-carboxyfluorescein, visible spectra, IR spectra, and electrical conductivity. Helical superstructures are obtained with Co(II) ion, although 3 does not contain any chiral center, whereas rodlike structures are formed with Fe(II), Fe(III), or Co(III) ion. Stabilization of bilayer membranes upon coordinative polymerization is demonstrated by enhanced resistivity to disruption in aqueous ethanol. In addition, it is shown that fluidity and rigidity of the coordinatively polymerized bilayer membranes can be balanced by changing the metal content.