Diffusion data from pulsed-field gradient spin-echo (PGSE) methods are shown to be qualitatively useful in the investigation of problems involving unknown molecular aggregation and/or the nature of inter-ionic interactions in metal complexes. For charged species possessing anions such as PF6-, BF4-, CF3SO3- or BArF-, both F-19- and H-1-PGSE methods offer a valid alternative and, sometimes, unique view of gross and subtle solution molecular structure and dynamics. Problems associated with solvents, concentration, and reproducibility are discussed.