Microband voltammetry is described in undiluted molten salts of Co(II) bipyridine complexes to which short (n = 1, 2, or 3 units) polypropylene oxide oligomers have been appended. It has been possible to measure cyclic voltammetric and potential step responses under conditions where the diffusion layer thickness formed in the electrolysis is demonstrably less than the diameter of the Co complex. Apparent diffusion coefficients recorded in the molecule-scale diffusion regime as a function of n and temperature range from 1 x 10(-14) to 1 x 10(-18) cm(2)/S. The corresponding bull, diffusion coefficients are ca. 7-fold smaller. The peculiar shape of the current-time response is rationalized as a "finite-diffusion" effect. Analysis of potential-step current-time results as the kinetics of a first-order electron transfer oxidation (of complexes adjacent to the electrode) gives rate constants quantitatively equal to the diffusion rate results, provided the latter are divided by the (Co complex diameter)(2) as the characteristic hopping distance of the interfacial electrochemistry. The kinetic data also agree with cyclic voltammetry rate constants if the difference in over-potential is taken into account.