In the LEGO project, we propose a new approach to realize the fabrication of 2D and 3D metal oxide structures, from solutions, using direct laser writing, layer by layer, without thermal post-processing, the layers being deposited by dip-coating. We aim at multi-scale structural control and hierarchical functionalities, with control and versatility of material structure (dense or mesoporous structures of metal oxides TiO2, ZrO2, HfO2, ZnO). Directed self-assembly (DSA) will be introduced to prepare 2D nanoporous thin films with controlled long-range organization. By extension in 3D, 3D hierarchical nanoporous structures will be obtained, with each layer serving as a guide for the next. The final 3D material can thus be built as a LEGO by precise positioning of each layer.