In present report, graphitic carbon nitride (g-C3N4) modified TiO2 mesoporous photoelectrodes were prepared and applied both as photoanodes for quantum dot sensitized solar cells (QDSSCs) and as photocatalysts for photodegradation of organic pollutant using Rhodamine B as pollutant model. Compared with TiO2 mesoporous photoelectrodes, the g-C3N4 modified TiO2 photoelectrodes exhibited obvious improvement in QDSSC device performances and photocatalytic activities. By optimizing the loading amount of g-C3N4, the champion power conversion efficiency of 2.91% was achieved using CdS QDs as sensitizer, showing 29.3% improvement compared with that of TiO2 electrodes. Meanwhile, the present photoelectrodes showed the excellent ability of photodegradation (96.3%) compared with TiO2 photo-electrodes. The improved behaviors of g-C3N4 modified TiO2 photoelectrodes were attributed to the formation of type II alignment between g-C3N4 and TiO2, which accelerated the separation of photogenerated carriers. Present work showed the multifunctional applications of g-C3N4/TiO2 photoelectrodes in optoelectrical conversion and photocatalyst. (C) 2016 Elsevier Ltd. All rights reserved.