An environment-friendly phosphotungstic acid catalyzed cross-dehydrogenative coupling reaction for the synthesis of 9-substituted-9H-xanthenes under oxygen and solvent-free conditions have been developed. The economic and practical reaction exhibited good substrate applicability tolerance, various 9-substituted-9H-xanthenes were synthesized in moderate to excellent yields by tuning the ratio of xanthenes and ketones (22 examples, up to 99% yield). By testing the photoelectrochemical performance, some of the xanthene derivatives (10c, 12c, 13c and 2d) showed stable photocurrent value, especially 2d had better cathode photocurrent value and application potential.