Abstract
Our recent study of the proton transfer in the double-well potential of the H-bonded charge-transfer (CT) crystals is introduced together with several other related topics. Special attention is focused on our investigation into the control of the dynamical motion of protons by using the excess a-electron effect on the hydrogen bonding in the CT-interaction system, which provides useful information in the design of a new molecular function using the H-bonded CT complexes. In this process, optical transitions enhanced by the dynamical motion of protons has been identified as the proton-linked super-CT transitions.