Beyond its biological interests, DNA is an excellent building block in material science and nanotechnology due to its unique molecular recognition capability and well-defined physical and chemical properties. Using DNA as information-rich construction material, it's feasible to engineer various static DNA nanostructures and dynamic DNA devices via programmed self-assembly. In this seminar, I will discuss three related topics: (1) design and construction of a family of symmetric DNA star motifs and using these motifs to assemble a variety of DNA 2D crystals and derived applications; (2) construction and characterization of well-defined DNA 3D nano-objects; (3) a ribosome mimetic DNA nanomechanical device that can mediate autonomous multi-step organic synthesis in a single isothermal solution