A diffusion-limited assembly approach was explored to fabricate symmetrical [Cu(Succinate)](n) microclusters with a different shape and size for the first time. The molecular structure of succinate and its coordination reaction capability towards copper(II) ions governed the one-dimensional growth of the nanofibers and the concomitant formation of the microclusters. In detail, a symmetrical concentration gradient was formed around the endpoints of the nanofibers caused by the diffusion-limited process at high reactant concentrations. The concentration gradient forced the nanofibers to grow divergently and further aggregate into open microcluster structure. The shape and size of the microclusters could be tuned by altering the concentration of the reactants. Particularly, mask-like double-hole symmetrical microclusters (MDHSMs) were obtained when the concentration of both reactants was as high as 140mM. The resultant MDHSMs showed high selectivity in adsorption of dyes and proteins, and may find potential applications in water treatment, bioseparation, and immobilization of biomacromolecules.