Silicon‐containing arylacetylene resins (PSAs) are promising thermal stability polymers for many applications. However, the controllability of curing reaction limited their application because of the high curing temperature and enthalpy. In this study, Materials Genome Initiative was utilized to screen out a target monomer, 2,7‐diethynyl‐9H‐fluorene (DEF), for design of new PSAs with low curing temperature and enthalpy. After incorporation of DEF, the obtained silicon‐containing fluorenylacetylene resins (PSA‐VBF) could be cured at a lower temperature of 149.2 °C with lower enthalpy (239.8 J g−1) than the reported PSA‐V (190.0 °C, 368.3 J g−1). Moreover, the thermal curing behavior and mechanism were investigated by differential scanning calorimetry, Fourier transform infrared, and pyrolysis‐gas chromatography–mass spectrometry. The results revealed that with the increased of DEF, the curing reaction of PSA‐VBF became dominated by Diels–Alder reaction. And the formed aromatic fused rings endowed the cured PSA‐VBF with excellent thermal stability, which were proved by thermogravimetric analysis results that the temperature at 5% weight loss (Td5) of the cured copolymers ranged from 630 to 639 °C, and the char yield at 1000 °C was above 90%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48262.