Although magnesium fulfills several essential biochemical roles, direct studies on this ion are complicated by its unfavorable spectroscopic characteristics. This contribution explores the possibility of monitoring magnesium - nucleic acid binding via a combination of [Co(NH3)(6)](3+) as surrogate for [Mg(H2O)(6)](2+), and of high-resolution solid-state Co-59 NMR as a spectroscopic probe. Such strategy quenches fast cationic exchanges between bound and free states, while exploiting the superior NMR properties of the Co-59 spin. Experiments on relatively small amounts of tRNA can then discern resonances corresponding to different metal binding environments, These characterizations were assisted by studies on model compounds and by multinuclear P-31-Co-59 recoupling experiments.