The synthesis of shape-controlled nanocrystals is very important for tailoring unusual properties. In this presentation, I will discuss several recently developed strategies based on the non-hydrolytic colloidal synthesis in controlling the size and shape of nanocrystals. Platinum-based nanostructures will be used as a model system to study the low dimensional forms, which are beyond the simple shapes, including the one-dimensional (1D) nanorods, and multipods and three dimensional dendrites. The effect of twin defects in face centered cubic metals on the formation of multipods will be analyzed. Besides platinum, this presentation will also cover our recent research results on the composition control and surface modification of metal, metal alloy and metal oxide nanoparticles.