This feature article discusses the concept of nanoarchitectonics, a post-nanotechnology approach that constructs functional materials and structures using nanounits of atoms, molecules, and nanomaterials. It emphasizes the importance of layer-by-layer assembly in creating asymmetric structures and hierarchical organization, which enables rational physical and chemical communications to develop advanced functional materials. The article explores recent examples of layer-by-layer assembly to illustrate the development of basic methods and advanced nanoarchitectonics systems aimed at practical applications. It covers four main areas: (i) advancement in basics and methods, (ii) physico-chemical aspects and applications, (iii) bio-chemical aspects and applications, and (iv) bio-medical applications. The article highlights the potential of layer-by-layer assembly in creating materials with advanced functionalities, such as thermoregulatory performance, electromagnetic interference shielding, flame retardancy, and chiral mirrors. It also discusses the application of layer-by-layer assembly in biofunctional systems, such as the development of artificial biomimetic systems that mimic biological processes, including ATP synthesis and cascade reactions. The article emphasizes the importance of controlling physical and chemical communications in materials to achieve desired functionalities, and it outlines the potential of nanoarchitectonics in various applications, including energy, environmental, and biomedical research. The article concludes that layer-by-layer assembly is a powerful technique for developing functions through physical and chemical communication, and it suggests that further research is needed to fully understand and optimize this method.This feature article discusses the concept of nanoarchitectonics, a post-nanotechnology approach that constructs functional materials and structures using nanounits of atoms, molecules, and nanomaterials. It emphasizes the importance of layer-by-layer assembly in creating asymmetric structures and hierarchical organization, which enables rational physical and chemical communications to develop advanced functional materials. The article explores recent examples of layer-by-layer assembly to illustrate the development of basic methods and advanced nanoarchitectonics systems aimed at practical applications. It covers four main areas: (i) advancement in basics and methods, (ii) physico-chemical aspects and applications, (iii) bio-chemical aspects and applications, and (iv) bio-medical applications. The article highlights the potential of layer-by-layer assembly in creating materials with advanced functionalities, such as thermoregulatory performance, electromagnetic interference shielding, flame retardancy, and chiral mirrors. It also discusses the application of layer-by-layer assembly in biofunctional systems, such as the development of artificial biomimetic systems that mimic biological processes, including ATP synthesis and cascade reactions. The article emphasizes the importance of controlling physical and chemical communications in materials to achieve desired functionalities, and it outlines the potential of nanoarchitectonics in various applications, including energy, environmental, and biomedical research. The article concludes that layer-by-layer assembly is a powerful technique for developing functions through physical and chemical communication, and it suggests that further research is needed to fully understand and optimize this method.