The results of combined in situ Fourier transform infrared spectrometric and ellipsometric investigations of three types of film are reviewed, and the complementary nature of these two powerful techniques is explored. The films were chosen to represent three possible levels of redox centre interaction, varying from the essentially independent in poly(4-vinyl-4′-methyl-2,2′-bipyridylrheniumtricarbonyl chloride) through optically coupled systems such as Prussian Blue to the strongly correlated systems exemplified by poly(pyrrole), and in each instance, the detailed behaviour of the film during growth and cycling can be derived.