Having confirmed the effectiveness of the dpa-based ligand scaffold, we examined the impact complexation with a variety of metals had on CA yeast cells and their antiadhesive activity. Since toxicity is a concern in medicinal chemistry when proposing metallodrug candidates, particularly as antiadhesives, toxicity assays were first performed to identify any fungicidal potential for this series of complexes (Figure S-30, ESI †). Upon incubating CA culture with various concentrations of 1Gal and its complexes, the nickel(II) complex was the only one to inhibit growth with any statistical significance, doing so even at concentrations as low as 63 μM (Figure ). One-way ANOVA analysis was performed at each concentration to determine statistical significance of results (p <0.1). Europium(III) complex [Eu⋅(1Gal)3](CF3SO3)3 exhibited no toxicity, a very encouraging result given its effectiveness against PA above, and likely impact on CA adhesion. In the pre-treatment exclusion assay, Figure , where each complex was tested at 0.1 mM, the Ni(II) complex was less effective than the ligand alone (22% inhibition), and it was observed that the yeast cells were particularly small compared to other experiments, a result that may be explained by this complex's toxicity, Figure . On the other hand, non-toxic complexes [Eu⋅(1Gal)](CF3SO3)3 and [Zn⋅(1Gal)2]Cl2 both outperformed the ligand (44%), without any unusual morphology of the fungal cells. The most effective antiadhesive was trileptic complex [Eu⋅(1Gal)3](CF3SO3)3, which inhibited 63% of adherence of CA cells to the BECs. This result at 0.1 mM was comparable with a tetravalent peptide-based dendrimer derivative of 3 which inhibits 64% of adhesion at 0.212 mM, but with much simplified synthetic procedure in the case of this work, merely requiring the assembly of lower-valency ligands in the presence of a metal ion, and slightly lower concentration. Competition assays with the same metal complexes, Figure , demonstrated very similar trends to those seen above. As in the pre-treatment assay, the Eu(III) complexes, when added to BECs at the same time as the yeast compete most effectively to prevent adherence of CA. The 1:3 complex inhibits 62% of adhesion and the 1:1 complex 53%. The Zn(II) complex also had an inhibitory effect of ca. 40%. In the presence of the 1:3 Eu(III) complex, clumping of fungal cells was observed under microscope, Figure . This had also been observed in the pretreatment assay. It may point towards a multivalentglycocluster mechanism of action for this compound relying on presentation of multivalent digalactoside epitopes in threedimensions, bringing together several pathogen cells, thereby preventing their adhesion to the human cells. This clumping, not observed for the slightly less antiadhesive 1:1 complexes, might present challenges in vivo, and thus must be considered carefully in further exploration of these systems. We are currently developing analogues of these ligands to include more conjugated chromophores which might allow for excitation of probes with blue light for potential fungal imaging applications; this may give further insight into the precise protein target of this class of anti-adhesive.