SYNOPSISNew azonitrile initiators carrying N-hydroxysuccinimide (ACPS) or biotin derivative (ACP-LC-B) moieties were synthesized from 4,4'-azobis(4-~yanopentanoic acid) (ACPA) with a yield of around 60%. Special care was taken in the assignment of the l3C-NMR resonances of the ACP-LC-B. The kinetic and thermal parameters associated with these initiators were determined by UV spectroscopy and differential scanning calorimetry.