Oxide semiconductors such as titania and zinc oxide offer low cost and environmentally benign materials for photocatalytic, solar-cell, electrode and sensing applications. The development for applications in the mentioned areas require optimization of the crystal quality and surface facets and often doping and/or addition of ultra-thin coatings. Solution based routes to thin film, nano-sponge and nano-particle structures will be presented, as well as doping with 3d and 4f elements. The possibility of extending the doping range beyond the thermodynamic stability through the use of alkoxide based precursors will be presented, as well as the surprising molecular-like local structure of Eu-oxide dopants in ZnO. Solution processing of thin- and ultra-thin films with promise to expand the available coatings compared to ALD will be presented for homo and heterometallic systems. The focus will be on synthesis and detailed structure, although properties will be mentioned in relation to the structures.