The azide-containing PEGylated AuNPs AuNP-4 produced through this ligand exchange procedure retain colloidal stability in biologically relevant media and show greater stability when compare with their counterparts obtained by BU synthesis. The presence of azide groups on AuNP-4 allows robust and versatile conjugation, employing two common click chemistry approaches (CuAAC and SPAAC). With its synthetic robustness, retained colloidal stability and biorthogonal addressability, the presented PEG-NHC@AuNP platform offers a unique opportunity for its being used in complex applications, e.g. biomedical sensing, diagnosis and delivery.