4‐oxo‐4‐(pyren‐4‐ylmethoxy) butanoic acid is used as a photolabile protecting group to show the opticalgating of nanofluidic devices based on syntheticionchannels. The inner surface of the channels is decorated with monolayers of photolabile hydrophobic molecules that can be removed by irradiation, which leads to the generation of hydrophilic groups. This process can be exploited in the UV‐light‐triggered