In this study, a novel non-metallic carbon-based catalyst co-doped with boron and nitrogen (B,N) was successfully synthesized. By precisely controlling the carbonization temperature of a binary mixed ionic liquid, we selectively modified the doping site structure, ultimately constructing a B,N co-doped frustrated Lewis acid-base pair catalyst. This catalyst exhibited remarkable catalytic activity, selectivity, and stability in the dehydrochlorination reaction of 1,1,2-trichloroethane (TCE). Detailed characterization and theoretical calculations revealed that the primary active center of this catalyst was the BN₃ configuration. Compared to conventional graphitic N structures, the BN₃ structure had a higher p-band center, ensuring superior adsorption and activation capabilities for TCE during the reaction. Within the BN₃ site, three negatively charged nitrogen atoms acted as Lewis bases, while positively charged boron atoms acted as Lewis acids. This synergistic interaction facilitated the specific dissociation of chlorine and hydrogen atoms from TCE, significantly enhancing the 1,1-dichloroethene selectivity. Through this research, we not only explored the active site structure and catalytic mechanism of B,N co-doped catalysts in depth but also provided an efficient, selective, and stable catalyst for the dehydrochlorination of TCE, contributing significantly to the development of nonmetallic catalysts.