A universally applicable synthesis route for the preparation of functionalized diazabicyclononane compounds was elaborated starting from a readily available 1,5-diphenyl-3,7-diazabicyclo[3.3.1] nonan-9-ol by alkylation of both secondary amines with modified benzyl residues containing a bromo, trimethylstannyl, trimethylsilyl, and pinacolboranyl residue. High yields (65–88 %) were achieved, supporting the intended purpose of these compounds: efficient mercuration reactions to stably bind Hg²⁺. Finally, the C-9 position of two functionalized diazabicyclononanes was further modified by introducing an azide functionality. This enables the conjugation to biomolecules of interest via click chemistry combined with a tracking by the introduced mercury isotopes.