In IR spectra, co-polymerization can be followed qualitatively, as characteristic bands of biphenyl moieties at 1416 cm -1 and 1000 cm -1 decrease in intensity when going from CTF-02 to CTF-02-Bpy (Figure ). At the same time, the characteristic bands of bipyridine moieties at 1467, 1050 and 1030 cm -1 appear.