AbstractMolecular electronic devices have gained extensive interest, owing to their low‐cost fabrication, easy characterization, low voltage operations, fast response to external stimuli, and innumerable applications that are not possible with the existing complementary metal‐oxide semiconductor (CMOS)‐based devices. Molecular ultrathin films of controllable thickness grown through the electroreduction method on conducting carbon electrodes can further enhance the interfacial stability of the molecular devices over thiolated self‐assembled monolayers, thus are more powerful for practical usages. A novel nanometric molecular electronic device with a stacking configuration of carbon/tetraphenylporphyrin/LiF/carbon demonstrates electric‐field‐ and polar‐solvent‐driven ion movements, producing high‐density charge storage ability and resonant charge‐transport mechanism at low bias <+1 V is highlighted here. The charge storage capability of the device enhances in CH3CN vapor as much as 78 fold over the dry measurement.