Photoelectrochemical overall water splitting by semiconductor electrodes modified with functional molecules has attracted considerable attention in recent years. Various kinds of molecular-based photoanodes consisting of a semiconductor thin film modified with both a photosensitizer (PS) and a water oxidation catalyst (WOC) have been developed thus far, and overall water splitting is achieved by using such a molecular-based photoanode and a Pt cathode. Nevertheless, due to the desorption of a PS and/or a WOC from the semiconductor surfaces, almost all the reported molecular-based photoanodes lose their photoelectrocatalytic activity within an hour. I am working on the development of highly durable and efficient molecular PECs by developing noverl PS and WOC based on pyridine anchoring Technique, which have excellent adsorption ability on TiO2 surface even in aqueous solution.