Thermally latent reaction of a copolymer (P1) bearing hemiacetal ester and n-butyl methacrylate moieties and glycidyl phenyl ether (2) was catalyzed by bis(p-methoxybenzylidene)-1,2-diiminoethane/zinc chloride complex (ZnCl2/3) at 30-150 degrees C for 6 h. No reaction of P1 and 2 took place below 70 degrees C, and it smoothly proceeded above 120 degrees C. The latencies and activities mean that ZnCl2/3 meets both the high latencies at ambient conditions and the high activities at desired temperatures. Thermal crosslinking reaction employing multifunctional derivatives was carried out using ZnCl2/3 at 140 degrees C for 6 h to afford a networked polymer in high yields. (C) 2008 Wiley Periodicals, Inc.