A coordination polymer has been formed at the water surface by reaction of the bifunctional ligand methylenebis(N-hexadecylsalicylidenamine) (MBSH) with bivalent metal ions, dissolved in the subphase. Studies have been carried out to elucidate the structure of this polymer in monolayers at the water surface as well as in Langmuir-Blodgett multilayers. Results with a similar low-molecular compound are included in the discussion. The collapse area in the monolayer at the water surface was strongly dependent on the metal ion concentration. The infrared spectrum of the copper complex Langmuir-Blodgett layer suggests complete conversion of MBSH, since no absorption of the free ligand could be detected. FTIR spectra revealed further, that complexation of copper ions took place between the nitrogen and the oxygen atom of the ligand.