Abstract4‐Aminoquinazolines and quinazolin‐4 (3H)‐ones, both labelled with carbon‐14 in the 4‐position, were prepared from 2‐aminobenzonitrile‐[cyano‐14C] and 2‐aminobenzoic acid‐[carboxy ‐14C] or 2‐amino‐ benzamide‐[carboxy ‐14C], respectively, using rapid, one‐pot procedures under microwave enhanced conditions. Copyright © 2009 John Wiley & Sons, Ltd.