Research in nanostructured materials is motivated by the belief that ability to control the building blocks or nanostructure of the materials can result in enhanced properties at the macroscale: increased hardness, ductility, magnetic coupling, catalytic enhancement, selective absorption, or higher efficiency electronic or optical behavior. Two approaches for the building up of nanoscopic features have been envisaged: top-down and bottom-up. Bottom-up approaches seek to have smaller (usually molecular) components built up into more complex assemblies, while top-down approaches seek to create nanoscale devices by using larger, externally-controlled ones to direct their assembly. This work is mainly dedicated to the self-assembly process of nanoparticles which are synthesized physically or chemically. Our target is to develop new nanoparticle self-assembly process based on the nanoparticles we have synthesized. To further expand our fabrication techniques to engineering applications, we have studied the electrical or optical properties of these nanomaterial structures and we have developed some new chemical sensors out of them.