We are interested in low-dimensional colloidal nanostructures, with a primary focus on monodisperse inorganic nanocrystals (NCs). With the presence of the surface-capping ligands, these colloidal NCs are versatile nanoscale building blocks for the bottom-up construction of mesoscopic and macroscopic superstructures with well-defined symmetry and geometry by self-assembly. Such NC-based superstructures and their carbonaceous derivatives may find wide applications in energy conversion and storage, catalysis, and optoelectronic devices.