Electrodeposited thin films of n-CdSe were anodically polarized under white light illumination in 0.01 M K-4[Fe(CN)(6)]/1.0 M KCl. The film mass increased parallel with anodic current flow as probed by combined linear sweep voltammetry/electrochemical quartz crystal microgravimetry measurements. This behavior contrasts with that observed for the parent 1.0 M KCl electrolyte wherein mass loss is observed because of photoanodic corrosion of n-CdSe. The mass increase in the present case is attributable to overlayer formation. Laser Raman spectroscopy (LRS) identifies this overlayer to be K-2[CdFe(CN)(6)] by comparison with the cyanide stretching bands of authentic samples of this compound. The redox behavior of this overlayer was probed by cyclic voltammetry and in-situ LRS measurements on Cd films derivatized with the overlayer. The [CdFe(CN)(6)](2-/-) redox could be monitored by both these techniques in 0.1 M NaNO3, attesting to the ability of the overlayer at n-CdSe to shuttle charge between the semiconductor and the electrolyte. The kinetics however are rather slow, and incomplete oxidation of the overlayer is obtained even after similar to 3 min anodic polarization in 0.1 M NaNO3. A high surface area of the Cd layer facilitates stable overlayer formation as borne out by comparison of the behavior of electrodeposited Cd film on Au and a polished Cd rod. Finally, the ramifications of this trend in terms of overlayer stability in operating photoelectrochemical cells are discussed.