Metal organic frameworks (MOFs) with aluminium, copper and iron as central metal atoms with 1,4-benzenedicarboxylic acid (aluminium) and 1,3,5-benzenetricarboxylic acid (copper and iron) as ligands are selective and active catalysts in promoting the polymethylation of aromatic amines with dimethyl carbonate (DMC). N-methylation prevails over carbamoylation even though they are competing parallel processes. The present N-methylation protocol using DMC enjoys advantages such as convenient reaction conditions, benign, reusable, cost-effective catalyst, avoids the use of additional solvent and uses a safe, green methylating agent that only produces CO2 and methanol as by-products. (C) 2010 Elsevier B.V. All rights reserved.