The objective of this study was to examine the curing behavior of bisphenol A-based cyanate ester resin (BADCy) containing various levels of catalyst using Nuclear Magnetic Resonance (NMR) and size exclusion chromatography (SEC). The reaction products were analyzed using SEC to obtain information on the molecular species distribution during the polymerization reaction. A kinetic scheme was derived to predict the species distribution in the reaction medium in the pregel region. The results show that trimerization reactions occur in the catalyzed systems under these conditions. The uncatalyzed system was found to be stable at room temperature. The species distribution in the pregel region during polymerization of cyanate monomer was derived based on kinetic relationships.