In the past eight years, there has been dramatic growth in the areas impacted by the concept and chemistry of “frustrated Lewis pairs” (FLPs). While the use of FLPs in stoichiometric and catalytic hydrogenations of imines was the first application to emerge, the development of such metal-free hydrogenations continues to grow with a broadening substrate scope, catalyst designs and selectivities. Substrates where such metal free reductions are possible include imines, enamines, silylenol ethers, enones, anilines, N-heterocycles, ketones and aldehydes. While a variety of electrophilic boranes continue to be exploited as catalysts, borenium cations as well as carbon-based electrophiles have been shown to be viable as well. Regio- and enantio-selective catalysts have also emerged, auguring well for potential in commercial applications. Concurrent with this rapid expansion of metal-free hydrogenation, theoretical and experimental studies continue to provide deeper insight into the mechanism of action of FLPs. The application of FLPs is not limited to H2 activation and indeed FLPs have been shown to react with a large range of small molecules such as olefins, alkynes, disulfides, B-H and C-H bonds, CO2, N2O, cyclopropanes, conjugated enynes, enones and diynes, SO2, RNSO and NO. Such a variety of reactivity is leading to the utility of FLPs in synthetic chemistry including CO2 reduction chemistry, radical polymerizations and hydroamination catalysis. The notion of FLPs has also been applied to target new Lewis acid/base reactivity, including carbon, silicon and phosphorus-based Lewis acids as well as metal-based FLPs. There is no doubt that exciting new developments will continue to emerge from this seemingly simple concept. This present issue of the Israel Journal of Chemistry focuses on FLP chemistry and illustrates new and continuing innovations and developments. The present works describe a variety of aspects of FLP chemistry, furthering this exciting new field at the confluence of inorganic and organic chemistry. 1 1 Doug Stephan Gerhard Erker University of Toronto Westfälische Wilhelms-Universität (Münster) Guest Editor Guest Editor