A new three-dimensional metal organic framework (MOF) containing Fe-II and Ag-I ions and 2-pyrazinecarboxylic acid (pcaH) was synthesized, and its magnetic and catalytic properties were studied. The MOF has a big window size of 12.1 x 12.0 angstrom, with 23.8% solvent-accessible space, and shows size selectivity toward Lewis acid catalysis.