Energy, environmental issues and health care are amongst the top priorities of modern society. Such issues have sparked phenomenal interest in inorganic nanomaterials as they hold great promise to develop new advanced devices and equipment which revolutionise the way we live. Investigating the structuration of materials on the nanoscale has revealed unprecedented physical (optics, magnetism, etc.) and chemical (e.g. catalysis) properties that are absent in bulk matter of the same chemical composition. These specific functionalities are the consequence of a complex multi-level organisation (chemical, structural, textural) of the architecture of inorganic nanomaterials. The global properties and functional performances largely depend on the extent to which these levels are mastered during the synthesis process.