The coordination of a mono(amido) triamine macrocyclic ligand Me 3 TACD derived from cyclen (1,4,7,10-tetraazacyclododecane or 12aneN 4 ) toward electropositive metal centers is surveyed. This NNNN-type monoanionic macrocyclic ligand is capable of stabilizing a variety of metal coordination environments that are commonly not amenable to stable coordination spheres. Metal complexes supported by Me 3 TACD include hydrides, hydrocarbyls, silyls, and amides. Protection of one hemisphere of a large metal center allows, as in the case of metallocene scaffolds for early transition metals, deaggregation and control of reactivity. The mono(amido) triamine macrocyclic ligand Me 3 TACD (Me 3 TACD)H = 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane is a versatile supporting ligand for a variety of electropositive metals.