Abstract In this paper, the problem of event-triggered output feedback synchronization control for complex dynamical networks (CDN) is studied. Based on a distributed state observer, a novel event-triggered mechanism is firstly introduced to design the output feedback synchronization controller, and by applying a useful graph theoretical result, the asymptotic convergence of the synchronization errors is then guaranteed. Moreover, it is proved that the designed event-triggered synchronization method is also valid for the CDNs with time-varying coupling weights. In particular, the proposed method is an extension of the existing state feedback event-triggered synchronization results. Finally, the circuit realizations for the new event-triggered mechanism and control approach are given, and the effectiveness of the proposed scheme is illustrated through the simulation results.