Chiwon Hwang†, Yeosan Lee†, Minjae Kim, Younggyu Seo, and Seung Hwan Cho*   The development of new approaches to installing diverse carbon fragments to a nitrogen atom has attracted considerable attention in chemical science. While numerous strategies have been devised to forge C(sp³)–N bonds, one conceptually powerful and straightforward approach is to insert a transformable sp³-carbon unit onto a nitrogen atom for modular diversification. Here we describe the successful synthesis of halo-diborylmethanes and their applications to the preparation of nitrogen-substituted diborylmethanes through their homologative coupling with a variety of nitrogen nucleophiles including biologically relevant molecules. This process exhibits a remarkably broad substrate scope, and the usefulness of the obtained compounds is demonstrated by the modular diversification of the diborylmethyl group to access various nitrogen-containing molecules.   https://doi.org/10.1002/anie.202209079