Spectroscopic ellipsometry has been used to investigate the optical properties of poly(ferrocenylsilane) polyion multilayer thin films in the visible and near-infrared range of the spectrum. The thin films were deposited using the layer-by-layer assembly process. Films with thicknesses of up to 55 nm were fabricated stepwise from polyelectrolyte solutions with a controlled ionic strength. These films allow an accurate characterization of the optical properties of poly(ferrocenylsilane) polyion layers. We show that the complex refractive index can be described by a simple Cauchy model. Refractive index values vary over the spectral range from 1.53 (near-infrared) to 1.8 (ultraviolet).