High curing temperature is the key disadvantage of cyanate esters. A novel catalyst system was developed, which is a hybrid catalyst system (HC) consisting of UV activated tricarbonyl cyclopentadienyl manganese (Catalyst I) and Catalyst II derived from dibutyl tin dilaurate. The effect of HC on the reactivity of 2, 2'-bis(4-cyanatophenyl) isopropylidene (BADCy) monomer, and that on the dielectric and thermal properties of cured resin were investigated. Results show that HC displays an attractive synergy effect on catalyzing BADCy over its two components. Compared with the curing exothermic peak of BADCy, that of BADCy/HC system appears at significantly lower temperature (which is at least 120 degrees C lower than the former). In addition, cured BADCy/HC resin also exhibits interesting synergy effect in integrated performance, that is, it has much better thermal resistance and dielectric properties than cured BADCy, BADCy/ Catalyst I, and BADCy/ Catalyst II resins. The BADCy/ HC resin can be used as high performance matrices for advanced composites and adhesives. POLYM. ENG. SCI., 51:2236-2244, 2011. (C) 2011 Society of Plastics Engineers