AbstractA novel one‐step synthesis of silicon‐containing arylacetylene resin (PSA) catalyzed by Et2Zn was reported. PSA‐Et2Zn was prepared by the reaction between diethynylbenzene and dichlorodimethylsilane in the presence of diethylzinc. The structure of PSA‐Et2Zn was determined and the reaction mechanism was proposed. In addition, the processability, thermal curing behavior, and thermal properties were studied. When compared with the zinc powder catalysis method, the Et2Zn catalysis method demonstrates a greater effectiveness in avoiding the formation of olefinic products at the ends of the molecular chain, which can improve thermal capabilities. The results show that PSA‐Et2Zn possesses excellent processability and thermal properties. PSA‐Et2Zn has a wide processing window of 35∼182 °C and the thermal crosslinking reactions of PSA‐Et2Zn resin are mild. The cured PSA‐Et2Zn shows high thermal stability with a residue yield up to 87.9 % at 800 °C. Furthermore, the temperature at 5 % weight loss in nitrogen and air atmospheres is 584 °C and 539 °C, respectively.