In this study, we employ a type of polyoxotitanate (POT) compound with a unique structure that is composed of a metal-oxo core and functionalized by catechol ligands, and characterize its electrochemical and photoresponsive properties. We find that the POT functionalized by the catechol ligand acts as a photoresponsive single source to provide the photocurrent in aqueous electrolyte. The first principles calculation confirms the intramolecular ligand-to-metal charge transfer characters. Considering the stable photocurrent output generated by the POT in the aqueous condition, we anticipate potential applications of the catechol-functionalized POT in the optoelectronic devices that require water stability and aesthetic features.