Advanced structural predictions, driven by first-principles calculations, facilitate the realization of a superconducting state under reduced pressure conditions while maintaining structural integrity. Scandium hexahydride (ScH₆) exhibits structural stabilities under high pressure, adopting hexagonal and body-centered cubic structures that lead to high-temperature superconductivity. In this study, we theoretically provide a crucial reference for boron-nitrogen-substituted hydrogen above 100 GPa. Subsequently, Sc(BN)₃ demonstrates significant structural stability, observed up to 200 GPa. Utilizing the stochastic self-consistent harmonic approximation sheds light on the influence of thermally excited lattice vibrations on the crystal structure of Sc(BN)₃, emphasizing the impact of quantum ionic effects. These findings underscore the distinctive anharmonic behavior of Sc(BN)₃, indicating its potential to facilitate boron-nitrogen-substituted hydrogen, which could find widespread applications in SC, achieving a critical temperature of 32.8 K under 150 GPa.