Gold glyconanoparticles (Au-GNPs) are multivalent tools based on self-assembled monolayers (SAMs) of thiol-ending glycoconjugates grafted onto gold nanoparticles by means of Au–S bonds. These hybrid multivalent systems show significant water solubility together with a good cell permeability, which is essential for therapeutic applications. Multivalent architectures bearing several bioactive units assembled onto a common scaffold showed to be more effective in improving the binding affinity to different kinds of carbohydrate-binding proteins, including enzymes, compared to their parent monovalent counterparts. This is defined as the “Multivalent Effect (MVE)”, and was investigated and observed to be successful also in glycosidase inhibition.  Iminosugars are glycomimetics with a nitrogen atom replacing the ring oxygen of sugars and are widely known to inhibit glycosidases. We recently prepared Au-GNPs decorated with pyrrolidine iminosugars, which were able to inhibit enzymes related to metabolic diseases.  By following a similar strategy, we now report the preparation and characterization of Au-GNPs decorated with ligands based on deoxynojirimycin (DNJ, Figure 1), a widely investigated iminosugar that has already shown excellent enhancement activities towards commercially available jack-bean α-mannosidase. Preliminary biological evaluation of these new multivalent architectures will be also presented.