Sol-gel coatings of tin doped indium oxide (ITO) were prepared via spin-coating, using a quasi single source precursor system that enhances homogeneous distribution of the dopant tin inside the oxide lattice. In addition, the implementation of metastable, bivalent tin into the gel layer enables the application of a one-step heat treatment under inert atmosphere, eliminating the need for the usually required critical post reduction treatment after crystallisation. The ITO layers produced were uniformly polycrystalline, with a homogeneous thickness of 60 nm. They showed increased electrical conductivity and optical performance in terms of transmission (vis) and IR reflection. The texture was less pronounced and the tensile residual stress determined in the layers was lower than in similar films, manufactured in a conventional two-step annealing process.