The sequential use of a hypervalent iodine reagent leads to the one-pot synthesis of 2-bromo/chloro-phenanthridinones via an amidation of arenes followed by a regioselective halogenation reaction. These consecutive C–H functionalization reactions can be used efficiently to construct 2-substituted-phenanthridinones at room temperature with good to high yields. Application of the current method is highlighted by the concise synthesis of the natural product PJ34.