Quinazolines are well known for their pharmaceutical importance as antibacterials, antitumours, antiparkinson and also show blood platelet antiaggregating activities. The Niementowski reaction is the explored for the synthesis of 3- substituted-4(3H)quinazolinones for which anthranilic acid, formic acid and aromatic or heteroaromatic amines are irradiated using "neat reaction technology" under microwaves without any solvent. This proved to be a high yielding protocol. Further study of 4(3H)quinazolinones as another possible Niementowski reaction is done by irradiating neat reactants, anthranilic acid, aromatic or aliphatic carboxylic acids and aromatic or heteroaromatic amines in microwaves to afford 2,3-disubstituted- 4(3H)quinazolinones within few minutes of irradiation.