The photocatalytic performance of graphitic carbon nitride (g‐C 3 N 4 ) is greatly hindered by weak absorption in the visible light region. In article number 1605148, Tierui Zhang and co‐workers report a new method to prepare nitrogen defective g‐C 3 N x with a controlled bandgap, through alkaliassisted thermal polymerization using various precursors. The optimized nitrogen defects can narrow the bandgap of g‐C 3 N x to harvest more visible light and facilitate charge separation, and thus contribute to the enhanced photocatalytic hydrogen‐evolution activity.