A set of graphitic carbon nitride samples was prepared using a straightforward experimental procedure without templates and any subsequent treatments. The materials were studied in‐depth using a range of physical and chemical methods such as X‐ray diffraction, FTIR spectroscopy, elemental analysis (CHN), nitrogen physisorption, SEM, XPS, TPD CO2. The resulting g‐C3N4 was shown to be highly efficient in carboxymethylation of cinnamyl alcohol with dimethyl carbonate yielding up to ca. 82 % of the desired cinnamyl methyl carbonate. In the studied conditions, an increase in the surface N atomic content leads to an increase in selectivity towards the desired carbonate, while a higher surface O content was beneficial for side products. Metal‐free graphitic carbon nitride was shown to be one of the most productive (ca. 2 mol/h kgcat) in the investigated reaction among studied heterogeneous catalysts.