New antibiotics are unquestionably needed in the fight to the emergence and spread of multidrug-resistant bacteria. So far, antibiotics targeting bacterial central metabolism have been poorly investigated. By determining the minimal inhibitory concentration (MIC) of desmethylphosphinothricin (Glu-γ-PH), an analogue of glutamate with a phosphinic moiety re-placing the γ-carboxyl group, we previously showed its promising antibacterial activity on Escherichia coli. Herein we synthetized and determined the growth inhibition exerted on E. coli by an L-Leu dipeptide derivative of Glu-γ-PH (L-Leu-D,L-Glu-γ-PH). Furthermore, we compared the growth inhibition obtained with this dipeptide with that exerted by the free amino acid, i.e. Glu-γ-PH, and by their phosphonic and non-desmethylated analogues. All tested compounds were more effective when assayed in chemically defined minimal medium. The dipeptide L-Leu-D,L-Glu-γ-PH had a significantly improved antibacterial activity (2 μg/mL), at a concentra-tion between the non-desmethytaled (0.1 μg/mL) and the phosphonic (80 μg/mL) analogues. Also in Bacillus subtilis the dipeptide L-Leu-D,L-Glu-γ-PH displayed an activity comparable to that of the antibiotic amoxicillin. This work highlights the antibacterial relevance of the phosphinic pharmacophore and proposes new avenues to the development of novel antimicrobial drugs containing the phosphinic moiety.