High molecular weight hyperbranched polyetherimides have been synthesized in a single-pot reaction in as little as 2.5 min from an easily synthesized and scalable AB(2) monomer using a rapid catalytic arylation method. NMR integration experiments and model compound studies revealed a degree of branching (DB) of 67% for hyperbranched polyetherimide 4 relative to the expected statistical value of 50%. Molecular weights were determined by gel permeation chromatography in two different solvent systems and varied widely. The polymers are highly soluble in common organic solvents and are among the most thermally stable hyperbranched polymers yet prepared.