Redox potentials were determined for solutions and thin films of hexadecafluorophthalocyaninatozinc (F16PcZn). A value of -0.6 V versus SCE was determined for the first reduction to the radical anion of F16PcZn.- in N,N'-dimethylformamide (DMF) and -0.9 V versus SCE for the second reduction to F16PcZn2-. Both potentials were shifted about 0.4 V towards positive potentials when compared to the unsubstituted phthalocyaninatozinc (PcZn) caused by the stabilization of the pi-system by the electron-withdrawing fluorine atoms in the ligand. Vapor-deposited thin films of F16PcZn on indium-tin-oxide (ITO) were reduced in contact with aqueous electrolytes of pH 5.5 to avoid H+-reduction in acidic regimes. A chemically reversible reduction accompanied by cation intercalation was found. The kinetics of the reaction were studied in detail by cyclic voltammetry under variation of the intercalating ionic species, the him thickness and sweep rare. From the charge uptake as well as from the dependence of peak current densities on the square root of the sweep rate it was found that the reaction rate is limited by the diffusion of intercalating cations. Optical absorption spectra were collected in situ. An irreversible structural change was observed during initial reduction, also in accordance with a strongly irreversible initial CV before the reversible behavior was obtained. The presence of the dianionic F16PcZn2- was detected even under conditions of an average charge uptake of less than electron/molecule. From the analysis of peak current densities according to the Randles-Sevcik equation as well as the observed charge flow dependent on film thickness and chronoamperometric characterization of the reaction a diffusion constant D-i for K+ in F16PcZn in the range from 1.6 x 10(-12) to 8.0 x 10(-12) cm(2) V-1 s(-1) was calculated.