Benzocyclobutene-terminated Bisphenol A polycarbonates (BCBPC’s) cross-link upon heating to form network polymers having excellent solvent and ignition resistance combined with good toughness over a wide range of cross-link densities. BCB PC’s having a wide range of molecular weights were prepared by the interfacial phosgenation of Bisphenol A and 4-hydroxybenzocyclobutene. These telechelic PC’s cross-link upon heating to temperatures above 200-degrees-C to form completely insoluble networks. Cross-linking kinetics estimated by DSC and rheological measurements are consistent with a first-order BCB homopolymerization process. Many of the mechanical properties of cross-linked BCB PC’s depend strongly on cross-link density. Particularly noteworthy is the high to moderate notched Izod impact strength of BCB PC’s over a wide range of cross-link densities. Any degree of cross-link density imparts improved ignition resistance in these materials due to the absence of melt dripping. Cross-linked BCB PC’s swell in good solvents for the un-cross-linked polymer in proportion to their cross-link density and do not suffer stress crack failure upon exposure to aggressive (to un-cross-linked PC) organic lipids such as acetone. At high cross-link densities BCB PC’s have a relatively high fracture toughness and show improved surface hardness. Above their glass transition temperatures cross-linked BCB PC’s show stable elastic moduli by dynamic mechanical analysis.