Some new 1,3-dihydro-1,3-dioxo-α -substituted-2H-isoindole-2-acetic acid derivatives of phenylboronic acid of compo-and -CH(CH 3 )C 2 H 5 ] have been prepared by the reaction of phenylboronic acid with N-protected amino acids in 1:1 and 1:2 molar ratios in dry refl uxing benzene. Plausible structures of these newly synthesized N-protected amino acid derivatives of phenylboronic acid have been proposed on the basis of physicochemical and spectroscopic studies. 11 B NMR data reveal the presence of tetracoordinated boron centers in these N-protected amino acid derivatives of phenylboronic acid.