A supramolecular catiomer with a metal-organic framework (MOF) motif was developed to manufacture messenger RNA (mRNA) assemblies. In contrast to the linear catiomer, the dendritic MOF catiomer appeared to markedly improve the colloidal stability of the mRNA assemblies, particularly affording substantial protection to the mRNA payloads from enzymatic degradation, eventually conducing to appreciable mRNA transfection activities at the targeted cells.