<p>The ability of bacteria to quickly adapt to environmental stresses, such as exposure to antimicrobial drugs, has necessitated a continued search for novel antibacterial agents with new mechanisms of attack, forever in competition with the rate of adaptation of these pathogens. Antibiotic resistant strains of a multitude of infectious diseases have appeared, imposing a huge burden from diseases once believed to have been reduced to minor health issues. Building on prior work, twenty-one new <i>N</i>-acyl-1-hydroxy-2,3,1-benzodiazaborinines were synthesized and characterized by high-field NMR, FTIR, ESI-MS, and other methods including X-ray crystallography for one unexpected structure. The syntheses by direct condensation using acylhydrazides gave products found to exist in one of three structural forms connected by (de/re)hydration reactions: open hydrazone (<b>a</b>), boron heterocycle (<b>b</b>), and anhydro dimer (<b>c</b>). Multisolvent ¹H and ¹³C NMR analyses showed that in solution these forms can readily interconvert in a solvent-dependent manner. The unanticipated structure of one target was established to be a rare ammonium borate salt arising from an extremely facile intramolecularly boron-catalyzed primary amide group hydrolysis. The new compounds were screened for activity against <i>Escherichia coli</i> in disk diffusion assays and seven of them demonstrated inhibitory activity, thus advancing the development of boron heterocycles towards the goal of producing next-generation antibacterial agents to combat persistently evolving resistant strains.</p><p></p>