Nucleophilic, anionic boryl compounds are long-sought but elusive species. We report that reductive cleavage of the boron-bromine bond in N,N ′-bis(2,6-diisopropylphenyl)-2-bromo-2,3-dihydro-1 H -1,3,2-diazaborole by lithium naphthalenide afforded the corresponding boryllithium, which is isoelectronic with an N -heterocyclic carbene. The structure of the boryllithium determined by x-ray crystallography was consistent with sp ² boron hybridization and revealed a boron-lithium bond length of 2.291 ± 0.006 angstroms. The structural similarity between this compound and the calculated free boryl anion suggests that the boron atom has an anionic charge. The ¹¹ B nuclear magnetic resonance spectrum also supports the boryl anion character. Moreover, the compound behaves as an efficient base and nucleophile in its reactions with electrophiles such as water, methyl trifluoromethanesulfonate, 1-chlorobutane, and benzaldehyde.