The design and synthesis of solid-state materials constructed from molecules has emerged as an important frontier of materials research. Molecular materials promise an unparalleled opportunity for systematic manipulation of solid-state properties and functions by using molecular design principles and capitalizing on the versatility of organic synthesis. Furthermore, the use of molecular components may produce considerable economic benefits, whether by reducing fabrication cost or through increases in performance. The articles in this issue of MRS Bulletin cover recent discoveries and developments based on materials with properties and functions that hinge on the characteristics of their molecular constituents. These materials promise significant advances in several technologies of substantial commercial interest, including organic light-emitting diodes, nonlinear optics, gas separations, chiral separations, and molecular magnets.

In recent years, a new class of porous materials based on a combination of organic components and metal centers has emerged, namely, microporous coordination polymers (MCPs), in which the chemical properties as well as the pore dimensions affect the incorporation of “guest” molecules within the pores. In this article, we describe the ability of MCPs to store gas molecules, which is ascribed to framework regularity and high porosity, and the unique capacity of certain MCPs to capture molecules selectively by well-defined interactions with organic functional groups.

Metal-organic frameworks (MOFs) are an interesting class of molecule-based hybrid materials built from metal-connecting points and bridging ligands. MOFs have received much attention, owing to their potential impact on many technological areas, including gas storage, separation, and heterogeneous catalysis. The modular nature of MOFs endows them with facile tunability, and as a result, properly designed MOFs can yield ideal heterogeneous catalysts with uniform active sites through judicious choice of the building blocks. Homochiral MOFs, which can be prepared by numerous approaches (construction from achiral components by seeding with a chiral single crystal, templating with coordinating chiral co-ligands, and building from metal-connecting nodes and chiral bridging ligands), represent a unique class of materials for the economical production of optically pure compounds, whether through asymmetric catalysis or enantioselective inclusion of chiral guest molecules in their porous frameworks. As such, homochiral MOFs promise new opportunities for developing chirotechnology. This contribution provides a brief overview of recent progress in the synthesis of homochiral porous MOFs and their applications in asymmetric catalysis and chiral separations.

Magnetic ordering that typically occurs for extended three-dimensional structured inorganic materials has also been established for several organic- and molecule-based materials. In addition to the characterization of new magnetic materials, new phenomena and combinations of phenomena have been observed for molecule-based materials. An overview of the new materials and phenomena is presented.

The self-assembly of small molecules into large, functional nanostructures has led to the construction of supramolecular systems, both in solution and on solid substrates, with defined dimensions that display unique properties through collective interactions, much like natural systems. In this article, we show how one assembles photo- and electroluminescent molecules through coordination chemistry for the purpose of producing novel materials that can be used for displays and lighting applications. In a stepwise process, we discuss the design and synthesis of the components, their spectroscopic behavior, and finally the properties arising from the assembly. We then move from molecules to more complex systems such as zeolite L nano-objects that can be used as nanocontainers and functionalized in different ways. We show how it is possible to organize rods of micron length in a geometrically controlled manner in solution and on surfaces. The assemblies are built by coordinative bonds and are luminescent materials that can be constructed from fluorescent building blocks, with potential applications as optoelectronic materials, in analogy to their molecular counterparts.

Two-photon/multiphoton lithography (MPL) has emerged as a versatile technique for the fabrication of complex 3D polymeric, hybrid organic/inorganic, and metallic structures. This article reviews some recent advances in the development of molecules and materials that enable two-photon and multiphoton 3D micro- and nanofabrication. Materials that exhibit high sensitivity for the generation of reactive intermediates are described, as are various materials systems that enable functional devices to be made and in some cases enable structures to be replicated. The combination of advances illustrates the opportunities for MPL to have a significant impact in the areas of photonics, microelectromechanical systems, and biomedical technologies.