A two-dimensional fabrication method was employed to assemble ultrathin multilayer films with specific three-dimensional structures by making use of interlayer and intralayer covalent bonding. The films were assembled in a layer-wise fashion on a silicon surface using bi- and multi-functional molecules as building blocks and strengthened by lateral cross-linking. The fabrication process could be controlled at the sub-nano-scale with the roughness of the surface after deposition of each layer within 0.2 nm. The film showed better resistance to harsh environments than randomly cross-linked or linearly linked films of comparable thickness. The combination of covalent LbL assembly and lateral cross-linking has significant potential as a method of fabrication for assembling nano-structures for a variety of applications. (c) 2012 Elsevier Inc. All rights reserved.