Metal-organic frameworks (MOFs) are typically synthesized via solvothermal reactions, whose reaction kinetics might be a bottleneck in the scaled-up manufacturing of these materials. Herein, we show that asymmetric cationic site occupancy within a mixed-metal citrate-based MOF.KM3(C6H4O7)(C6H5O7)center dot xH(2)O (M = Co, Zn), also known as UTSA-16.can be exploited for improved formation kinetics. Using this strategy, mixed-metal UTSA-16 can be crystallized under significantly milder conditions relative to the parent Co-based one, paving the way for the mass production of this promising material.