The electrochemical differences between the Regions A, B and C is shown Figure for [Rux|Coy]n[Fe]6. In region A, no electrochemical oxidation of complex 3 is visible. The low percentage of the ruthenium complex 1 (blue) does not mediate electron transfer. In Region B (red) and C (black), the percentage of complex 1 is sufficiently high to allow electron transfer within the assembly. The oxidation potentials are significantly shifted to 1.5 V (Region B) and 1.3 V (Region C) in comparison to [Fe]6 (1.1 V). This overpotential is a result of the presence of the insulating cobalt complexes 2. Additional discussion about regions A and C are included in the Supporting Information, as well as additional data of Region B (Figure ). The films were analyzed using electrochemical impedance spectroscopy (EIS) to obtain information regarding their charge transfer resistance (Rct) (Figure ). We observed that the Rct value becomes smaller upon increasing the amount of the ruthenium complexes (1). For example, [Ru40|Co60]3[Fe]6 shows higher resistance towards charge transfer (Rct ≈ 20 kΩ) compared with [Ru90|Co10]4[Fe]6 (Rct ≈ 0.5 kΩ) (Figure and). The EIS measurements confirm that the ruthenium complexes (1) lower the resistance towards the oxidation of iron complexes (3), whereas the cobalt complexes (2) insulate components with respect to the WE surface. The EIS results confirm the observation we achieved using voltammetry methods. For region A, the amount of complex 1 is low, resulting in high Rct values (230-50 kΩ) and no electrochromic activity. For regions B and C, since complex 1 is more dominant within [Rux|Coy]n, a lower voltage is required to oxidize the iron (3) layer (Figure ); the charge remains trapped in this layer. The resistance of these films is also lower (Rct = 20-0.5 kΩ). The trapped charge can be released upon demand by exposing the oxidized films to a chemical reduction agent resulting in electrochemical-to-chemical energy transfer. The orange films turned purple within 2 s in an aqueous solution containing ferrocyanide (5 mM), owing to the low redox potential of the ferrocyanide (Eox = 0.35 V) (Scheme 1D). This observation suggests an outer-sphere electron transfer between the ferrocyanide and the on surface trapped [Fe 3+ ] of the redox-active layer. The reversibility of this redox process was evaluated using a combination of spectroelectrochemical measurements (for charge trapping) with the abovementioned charge release procedure. Upon applying 1.6 V, the MLCT band of the divalent iron complexes 3 (λmax = 570 nm) was reduced from 0.37 to 0.05, as one would expect for the formation of Fe 3+ species (Figure ). This characteristic band reappears upon chemical reduction. This charge trapping-release procedure was repeated eight times, indicating a stable and reversible electrochemical/chemical redox pathway. A control measurement in distilled water showed that the chemical reduction reagent is essential to release the charge (Figure ).