Two crystalline metal–organic frameworks formulated as Zn6(NDC)5(OH)2(DMF)2·4D MF, MOF-48, and Zn7(m-BDC)6(OH)4(H2O) 2·6DMF·4H2O, MOF-49, (NDC = 1,4-naphthalenedicarboxylate; m-BDC=1,3-benzenedicarboxylate) have been synthesized and fully characterized by single crystal X-ray diffraction studies, which reveal that the frameworks are constructed from pentagonal antiprismatic (MOF-48) and cuboctahedral (MOF-49) secondary building units respectively, however, both are reticulated into 3-D structures having the B network of CaB6.