The unprecedented development of DNA nanotechnology has caused DNA self‐assembly to attract close attention in many disciplines. In this research news article, the employment of DNA self‐assembly in the fields of materials science and nanotechnology is described. DNA self‐assembly can be used to prepare bulk‐scale hydrogels and 3D macroscopic crystals with nanoscale internal structures, to induce the crystallization of nanoparticles, to template the fabrication of organic conductive nanomaterials, and to act as drug delivery vehicles for therapeutic agents. The properties and functions are fully tunable because of the designability and specificity of DNA assembly. Moreover, because of the intrinsic dynamics, DNA self‐assembly can act as a program switch and can efficiently control stimuli responsiveness. We highlight the power of DNA self‐assembly in the preparation and function regulation of materials, aiming to motivate future multidisciplinary and interdisciplinary research. Finally, we describe some of the challenges currently faced by DNA assembly that may affect the functional evolution of such materials, and we provide our insights into the future directions of several DNA self‐assembly‐based nanomaterials. This article discusses the significant roles of DNA self‐assembly in materials science and nanotechnology, including the formation of hydrogels, induced three‐dimensional crystallization, the templated synthesis of conductive polymers, and nanomedical vehicles. In particular, the designability, specific recognition, and inherent dynamics enable DNA self‐assemblies to be the key elements in regulating the functions of DNA‐based bulk‐scale and nanoscale materials.