Reaction dynamics for electric field‐induced electron transfer have been studied for two systems, a spiro‐switch molecular system first proposed by Aviram as a possible building block for a molecular device, and a mixed‐valence di‐&mgr;‐oxo bridged manganese complex selected as a candidate for detecting field‐dependent crystal structures. The electric field dependence of the energetics of the molecular switch points to the key role played by the dipole moment of the precursor state. This finding is supported by the results obtained for the mixed‐valence complex, which however exhibits a markedly different behavior. In this case the polarizability of the complex is responsible for drastically different electric field dependent energetics. The switching field, the field at wich the electron transfer rate is largest, is predicted to be significantly higher for the manganese complex than for the spiro‐switch. We conclude that low‐field switching as desired for molecular device will require charge separation large enough for polarizability effects to be negligible, but not so large that there would be no overlap between the donor and acceptor states.