Solution based processes have gained much interest for the preparation of complex nano-structured materials. Benefits are found in the often direct and simple processing routes allowing for large-scale technological exploitation of the processes without the use of complex and size and shape limiting vacuum equipment needed for physical and chemical vapour deposition. The solution chemical routes span a wide range of sub-disciplines that have developed rapidly during the recent decade to produce unique and high quality materials of various shapes and complexities.
     Here solution based routes to complex nano-structured materials in different forms representing different kinds of complex structuring and areas of use will be presented, as well as some of their properties relating to renewable energy and electronics. Some topics covered are: doped and un-doped oxide semi-conductors e.g. ZnO:Eu nano-sponges, a-Fe₂O₃:Ti and TiO₂ films and nano-particles, multi-layer LSMO/CFO/LSMO thin films, complex composition ultra-thin coatings, metal-in-ceramic nano-composites and nano-structured metal. A particular focus is paid to the connection between the precursor system and the final material, and the dependence on the processing parameters. A wide range of experimental techniques were used to describe the reactions and microstructural changes during solution processing, heat-treatment and final structures, i.e. TG/DSC, XRD, IR spectroscopy, GI-XRD, XPS, EXAFS, (S)TEM-EDS/HAADF/EELS/ePDF. Optic, magnetic and catalytic properties were also investigated.