Three s-triazine-based functional monomers with thermo-polymerizable propargyl-ether units were synthesized by a facile procedure. These monomers can be thermally cured to form the crosslinked networks, which showed 5-wt% loss temperature of up to 400 degrees C and the char yields of more than 50% at 1000 degrees C. Moreover, the crosslinked networks exhibited the coefficients of thermal expansion (CTE) of below 43 ppm degrees C-1 varying from 30 to 300 degrees C and glass transition temperatures (T-g) of up to 290 degrees C, respectively. These monomers were also used to improve the thermostability of a commercial bismaleimide (4,4'-bismaleimidodiphenylmethane). The results indicated that blending the bismaleimide and the triazine monomers gave the new resins, which showed higher T-g and lower CTE than the bismaleimide, suggesting the triazine monomers can be considered as the modifiers for enhancement of the thermostability of the commercial bismaleimides. (C) 2016 Elsevier Ltd. All rights reserved.