Cobalt isopropyl xanthate thin films (CXTFs) were deposited via chemical bath deposition onto different substrates:commercial glass (CG), indium tin oxide (ITO), and poly(methyl methacrylate) (PMM). Isopropyl xanthate was synthesized according to a method de-scribed in the literature. The cobalt nitrate and isopropyl xanthate were mixed in a beaker, which allowed the thin films to be deposited via a simple ion–ion mechanism. The transmission, reflectivity, refractive index, dielectric constant, and optical conductivity were investigated for various thin films coated onto different substrates. An ultraviolet-visible spectrophotometer was used to measure the optical properties of the thin films. The lowest value of the transmission and the highest value of the refractive index were observed for the thin films deposited onto PMM. The structure of the cobalt xanthate was characterized by Fourier transform infrared (FTIR) spectroscopy, which was measured using a Perkin?Elmer Spectrum 400 spectrometer. The stretching vibration of the Co–S bonds was observed at 359 cm?1 in the FTIR spectrum of the CXTFs.