The development of metal–organic frameworks (MOFs) as microporous electronic conductors is an exciting research frontier that has the potential to revolutionize a wide range of technologically and industrially relevant fields, from catalysis to solid-state sensing and energy-storage devices, among others. After nearly two decades of intense research on MOFs, examples of intrinsically conducting MOFs remain relatively scarce; however, enormous strides have recently been made. This article briefly reviews the current status of the field, with a focus on experimental milestones that have shed light on crucial structure–property relationships that underpin future progress. Central to our discussion are a series of design considerations, including redox-matching, donor–acceptor interactions, mixed valency, and π-interactions. Transformational opportunities exist at both fundamental and applied levels, from improved measurement techniques and theoretical understanding of conduction mechanisms to device engineering. Taken together, these developments will herald a new era in advanced functional materials.

Metal–organic framework (MOF) materials are well known as elegant gaseous energy-storage materials, but their potential for electrical energy storage has only recently been explored. Although numerous studies have focused on MOF-derived porous carbon or nanoscale metal oxide materials, less attention has been paid to the intrinsic properties achievable through the molecular design of MOFs. Indeed, the porous nature of MOF architectures is highly suitable for accommodating electrolyte ions in electrochemical processes, suggesting their potential as high-performance active materials for batteries. In this article, we consider recent examples employing MOF materials as battery electrode materials. Redox-active sites were incorporated on metal junctions, ligands, or both, in the MOF structures. In addition, we introduce novel electrochemical mechanisms observed in the electrochemical process of MOF electrode materials.

Metal–organic frameworks (MOFs), with their crystalline nanoporous three-dimensional structures, have emerged as unique multifunctional materials that combine high porosity with catalytic, photophysical, or other properties to reveal new fundamental science and applications. Because MOFs are composed of organic molecules linking metal centers in ways that are not usually conducive to the formation of free-charge carriers or low-energy charge-transport pathways, they are typically insulators. Accordingly, applications so far have harnessed the unique structural properties and porosity of MOFs, which depend only to a small extent on the ability to manipulate their electronic structure. An exciting new area has emerged due to the recent demonstration of MOFs with controlled electronic and optical properties, which is enabling new fundamental science and opens up the possibility of applications in electronics and photonics. This article presents an overview of the fundamental science issues related to controlling electronic and optical properties of MOFs, and how research groups worldwide have been exploring such properties for electronics, thermoelectrics, photophysics, and charge storage.