<p>This work addresses predefined-time bipartite consensus (PTBC) for networked Euler-Lagrange systems (NELSs) subject to heterogeneous time-varying disturbances under dynamic leaders. A distributed control framework is proposed, systematically integrating a nonlinear disturbance observer (NDO), velocity observer, and integral sliding mode controller. Firstly, a NDO is constructed to estimate unknown disturbances in user-defined time frames, eliminating the requirement for prior knowledge of disturbance characteristics. Subsequently, a predefined-time velocity observer is synthesized for follower agents to reconstruct the desired velocity profile. Finally, an integral sliding surface incorporating topology-weighted consensus errors is constructed, ensuring predefined-time convergence of both sliding motions and bipartite tracking errors while effectively suppressing chattering phenomena. Notably, the observation and convergence times can be preconfigured independently according to operational requirements. To validate the proposed framework, numerical simulations are conducted on a two-link manipulator system. Simulation studies confirm the efficacy of the proposed control scheme.</p>