We report a comparative study on the activity of a series of five binary catalysts derived from various reported aluminum-based complexes. A benchmarking of their initial rates in the coupling of various terminal and internal epoxides in the presence of three different nucleophilic additives has been carried out providing for the first time a useful comparison of activity metrics in the area of cyclic organic carbonate formation. These investigations provide a useful framework how to realistically valorize relative reactivities and which features are important to consider the ideal operational window of each binary catalyst system.