For the latter half of the ‘Solid State 20th Century’ materials science has been the engine that propelled technology. As we enter the ‘Materials 21st Century’ it is abundantly clear that the insatiable demand for new materials for emerging technologies is driving materials synthesis and change. Materials chemistry will play a central role in this endeavor through the creation of materials with structures and properties able to meet the demands required by up-and-coming technologies. In this paper a far-sighted and innovative materials chemistry strategy is proposed. It takes solid state chemistry beyond fifty years of thermodynamic phases and microscale structures, to a new era of self-assembly chemistry focused on metastable phases and mesoscale structures, with accessible surfaces and well defined interfaces that determine function and utility. It is an interdisciplinary approach that combines synthesis, solid state architecture and functional hierarchy to create an innovative strategy for materials chemistry in the new millennium. The attractive feature of the approach is the ability to assemble complex structures rationally from modular components and integrate them into self-assembling constructions for a range of perceived applications. By creating a series of purposeful design strategies it is believed that truly revolutionary advances in materials science and technology can result from this approach.