The cure kinetics of a liquid dicyanate ester monomer which reacts to form a thermoset polycyanurate material (Tg≈200°C) have been investigated for both uncatalyzed and catalyzed systems. The reaction is satisfactorily described by a model of two simultaneous reactions. Tg versus time curves at various isothermal cure temperatures are calculated and compared to DSC experimental results for the uncatalyzed system, using the kinetic rate constants obtained from FTIR isothermal cure studies and the unique relationship between Tg and conversion obtained from DSC studies. The DSC Tg versus conversion experimental data for the catalyzed system are fit by the same model; the time-temperature-transformation (TTT) isothermal cure diagram for the catalyzed system is then calculated and compared to experimental TBA results. Macroscopic gelation is found to occur at a Tg of 75°C and a fractional conversion of 0.64 in the catalyzed system.