A method of preparation of a catalyst of N-containing/N-doped carbons and carbon nitrides said method comprising:

• Preparing at least one N-containing/N-doped carbon materials with nitrogen containing carbon precursors;
• Pyrolyzing the resulting carbon nitrogen-containing/-doped carbon and carbon nitrides – in the temperature range of 500-1000°C
• Centrifuging and washing the material with ethanol; drying to obtain the N-containing /N-doped porous carbons and carbon nitrides.

• wherein N-containing/N-doped carbons/carbon nitrides additionally is methylated by suspending N-doped mesoporous carbon in methyl iodide (CH3I) reagent under stirring at 40- 100°C (for 1-12 h) & centrifuging and washing the material with ethanol; drying to get the N- methylated N-containing/N-doped carbons/carbon nitrides.
• The method of catalyzing one of the organic transformations such as N-alkylation of amines; C-alkylation of ketones; and synthesis of quinolines said method comprising steps of: reacting the mesoporous N-containing/N-doped carbons and carbon nitrides catalyst prepared with respective amines or ketones or quinolines with the alkylating reagent in a tube reactor charged with inert gas in atmospheric pressure at temperatures 80- 140 °C for period of 1-24 h, wherein the catalyst is 5-50 wt% with respective amines, ketones and quinolines in the presence 0.01 – 0.5 equivalent of a base; carrying out the reaction by stirring magnetically in hot oil bath.