An efficient and general protocol for the synthesis of functionalized 2,4,6-triaryl pyridines and pyrimidines was developed from commercially available aromatic ketones, aldehydes and hexamethyldisilazane (HMDS) as a nitrogen source under microwave irradiation. In this multicomponent synthetic route, Lewis acids play an important role in selectively synthesizing six-membered heterocycles, including pyridines (1N) and pyrimidines (2N), by involving [2 + 1 + 2 + 1] or [2 + 1 + 1 + 1 + 1] annulated processes.