Function-inspired design of molecular building blocks for their assembly into complex systems has been an objective in engineering nanostructures and materials modulation at nanoscale. This article summarizes recent research and inspiring progress in the design/synthesis of various custom-made chiral, switchable, and highly responsive molecular building blocks for the construction of diverse covalent/noncovalent assemblies with tailored topologies, properties, and functions. Illustrating the judicious selection of building blocks, orthogonal functionalities, and innate physical/chemical properties that bring diversity and complex functions once reticulated into materials, special focus is given to their assembly into porous crystalline networks such as metal/covalent–organic frameworks (MOFs/COFs), surface-mounted frameworks (SURMOFs), metal–organic cages/rings (MOCs), cross-linked polymer gels, porous organic polymers (POPs), and related architectures that find diverse applications in life science and various other functional materials. Smart and stimuli-responsive or dynamic building blocks, once embedded into materials, can be remotely modulated by external stimuli (light, electrons, chemicals, or mechanical forces) for controlling the structure and properties, thus being applicable for dynamic photochemical and mechanochemical control in constructing new forms of matter made to order. ... mehrThen, an overview of current challenges, limitations, as well as future research directions and opportunities in this field, are discussed.