Novel physical or chemical properties are expected in a great variety of materials, in connection with the
dimensionality of their structures and/or with their nanostructures, hierarchical superstructures etc. In
the search of new advanced materials, the hydrothermal technique plays a crucial role, mimicking the
nature able to produce fractal, hyperbranched, urchin-like or snow flake structures. In this short review
including new results, this will be illustrated by examples selected in two types of materials, phosphates
and phosphonates, prepared by this method. The importance of the synthesis parameters will be
highlighted for a magnetic iron based phosphates and for hybrids containing phosphonates organic
building units crystallizing in different structural types.