Tuned chemical conditions complemented with a set of treatments have been developed to enhance the thermal stability of transition metal oxide mesoporous thin films (up to 500 °C for TiO₂ and 450 °C for ZrO₂), allowing the formation of crack-free coatings presenting excellent optical quality (transmittance higher than 85% in the visible region), tailored thickness (from 50 to 700 nm), a highly organised cubic (Im3m space group for TiO₂) or 2D-hexagonal (P6m space group for ZrO₂) mesostructure, high surface area (140–200 m² g⁻¹), controlled and narrowly distributed mesopore size (25–80 Å), and a nanocrystalline inorganic framework (anatase or tetragonal zirconia).