Transparent thin films were prepared by a sol-gel method starting from precursor formation in solution, subsequent spin coating followed by a heating ramp up to a maximum of 700 °C. Starting from a Bi ₂MoO ₆ synthesis route, the phase formation and thin film processing of the bismuth containing materials Bi ₂WO ₆, Bi ₃Ti ₄O ₁₂ and additionally of the tungsten-bronze structure Sr _0.75Ba _0.25Nb ₂O ₆ were studied. Spin coating was used to adjust the film thickness in a wide range from 6 to 200 nm. All films were obtained as multicrystalline pure phases according to X-ray diffraction analyses. Scanning electron micrographs revealed homogeneous coatings composed of nanoparticles with a crystallite size varying between 20 and 100 nm, furthermore the UV-VIS spectra demonstrated a high transparency of the films, 80-90% at 600 nm.