The exchange of the monocarboxylate ligand of the zirconium methacrylate oxocluster Zr(6)O(4)(OH)(4)(OMc)(12) (OMc = CH(2)=CH(CH(3))COO) with dicarboxylic acids (trans,trans muconic acid and terephthalic acid) leads to porous zirconium dicarboxylates exhibiting the UiO-66 architecture; the mild reaction conditions allow the control of their particle size.