UV irradiation of aqueous solutions containing various metal ions (Ag, Rh, Cu, Pb, Ba,.) and sensitizers was performed in order to synthesize a large variety of solid nano- or microcrystalline materials in the irradiated solutions and illustrate the chemical and photochemical reactions leading to their formation. Acetone was shown to be a very effective sensitizer and photoreducing agent when coupled with propan-2-ol, whereas formate HCOO- was introduced either mainly as a reducing agent in deaerated solution or as a source of nascent CO2 in the presence of air. It was shown that UV irradiation allows for the preparation of a wide variety of inorganic materials. Moreover, reactions mechanisms discussed may occur during Laser Ablation in Liquid processes.