Wide bandgap (WBG) and high thermal stability pseudobrookite compounds, Fe1+xTi2−xO5 (0 ≤ x ≤ 1), are promising materials for photocatalysis, high-temperature thermoelectric applications, green production of hydrogen by water splitting, fabrication of power electronics, and optoelectronic devices. Here, we report on WBG, polycrystalline, ferropseudobrookite, FeTi2O5, coatings, stable at high temperature, prepared by an optimized sol-gel route on fused silica and silicon substrates. The chemical composition, the amorphous-to-crystalline phase transformation, and the influence of the annealing temperature and atmosphere (air and argon) on the formation and evolution of the crystalline phases were investigated in detail by combining thermogravimetric and differential scanning calorimetry analysis with Fourier-transform infrared spectroscopy and X-ray diffraction. The experimental results clearly show that …