These results point to an interaction with PAO1 bacteria in vitro for this range of complexes that demonstrate low toxicity, but nonetheless in the case of Eu(III) complexes in particular, metal coordination gives rise to a carbohydrate-targeted biofilm inhibition effect that is noteworthy, particularly in the case of complexes with a 1:1 stoichiometry. The largest effect measured at subinhibitory concentration, at approximately 50% decrease in biofilm formation vs control compares favourably with Ru(II) and Ag(I) complexes reported previously. Given that activity relies on the identity of the carbohydrate epitope as well as the metal ion, it is considered likely that some of these complexes might also be effective for antiadhesive therapeutic effects against other pathogens with relevant receptors for galactosides.