Structural control of nanomaterials is of paramount significance for nanodevice fabrication. The first part of this talk aims to give a general introduction to the nanostructures synthesized in my lab. I will highlight the concept, strategy, and scope of our recent works. We have so far demonstrated several basic concepts for the colloidal synthesis of complex nanostructures, for example, use of polymer shells as nanocapsules to protect the assembly of nanoparticles, development of methods for isolating high-purity dimers and trimers of nanoparticles; use of polymer shells to break the symmetry of nanoparticles. Focused discussion will be given on our recent papers on the formation of nanoscale metallic double helices and the tuning of Au-Ag interfacial energy by embedding ligands in between metal layers. Our short-term goal is to impart specific functionalities to a judiciously designed nanostructure, where the different components could coordinate to achieve a useful function. Our long-term goal is to emulate the synthetic methodologies of organic chemistry and fabricate nanodevices by multi-step and rational colloidal syntheses.