Boronated polymers have proven great potential and versatility for a variety of applications. In this work, poly (isobutylene-alt-maleic anhydride) (PIMA) is chemically modified with benzoxaborole to yield the anionic boronated polymer, PIMA-Bx, a bifunctional dynamic covalent material operative at physiological pH. Benzoxaborole is incorporated into the polymer backbone via a spontaneous ring opening reaction followed by basic hydrolysis. Affinity studies with model ligands and a custom synthesized glycopolymer derived from PIMA are performed using fluorescence spectroscopy and microscale thermophoresis (MST), confirming full accessibility to benzoxaborole binding sites and pH modulation of the B-O interaction. Supramolecular assemblies between complementary PIMA polymers are studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM), revealing nanosized structures modulated by pH changes in the range 5-7.4. In vitro cell experiments demonstrate excellent biocompatibility of PIMA-Bx with cultured cells even at very high concentrations. Furthermore, fluorescence confocal microscopy (CLSM) confirms successful internalization of the benzoxaborole-grafted PIMA in HeLa and A549 cells. The boronated polymer also exhibits antibacterial activity per se against typical Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus. Therefore, this new boronated polymer, which is easily prepared using cost-effective materials, is an attractive material for biomedical and pharmaceutical applications.