A template-assisted synthetic method including the thermal polycondensation of guanidine hydrochloride (GndCl) was utilized to synthesize highly-organized mesoporous graphitic carbon nitride (mpg-C 3 N 4) photocatalysts. Comprehensive structural analysis of the mpg-C 3 N 4 materials were performed by XPS, XRD, FT-IR, BET and solid-state NMR spectroscopy. Photocatalytic performance of the mpg-C 3 N 4 materials was studied for the photodegradation of several dyes under visible and UV light illumination as a function of catalyst loading and the structure of mpg-C 3 N 4 depending on the polycondensation temperature. Among all of the formerly reported performances in the literature (including the ones for Degussa P25 commercial benchmark), currently synthesized mpg-C 3 N 4 photocatalysts exhibit a significantly superior visible light-induced photocatalytic activity towards rhodamine B (RhB) dye. Enhanced catalytic efficiency could be mainly attributed to the terminated polycondensation process, high specific surface area, and mesoporous structure with a wide pore size distribution. Keywords Graphitic-C 3 N 4 Á Carbon nitride Á UV-Vis light Á Photocatalytic degradation Á Organic dyes Electronic supplementary material The online version of this article (