While graphene-based lubricants are well-studied, the tribological potential of emerging carbon–nitride and carbon–boron 2D materials remains largely unexplored. Herein, by using first-principles calculations implemented in the VASP code, we systematically explored the interlayer interactions and frictional properties of bilayer homojunctions and heterostructures composed of graphene, C₃N, and C₃B. The DFT-D3 dispersion correction was employed to accurately capture the interlayer van der Waals forces. The results reveal that C₃N/C₃N, C₃N/graphene (C₃N/Gra), and C₃B/graphene (C₃B/Gra) systems exhibit significantly lower friction coefficients compared to pristine bilayer graphene (Gra/Gra). Notably, the sliding potential barrier of the C₃N/Gra heterostructure is only ~0.45 meV/atom (approximately 1/10 that of the Gra/Gra system), manifesting exceptional superlubricity and considerable potential for superlubricant applications. The sliding potential barrier of the C₃B/C₃N heterostructure is slightly smaller than that of Gra/Gra. In contrast, the C₃B/C₃B homojunction exhibits high resistance to sliding; under normal loads of 1–4 nN, its potential barrier ranges from ~16 to ~115 meV/atom, which is consistently twice that of Gra/Gra. The observed frictional variations are attributed to sliding-induced interfacial charge redistribution. These findings provide fundamental insights into the tribological behavior of C₃N- and C₃B-based materials and establish a quantitative link between frictional properties and interfacial charge dynamics, offering a theoretical basis for the development of advanced graphene-derived lubricants.