An isoreticular series of metal-organic frameworks (MOFs) with the ftw topology based on zirconium oxoclusters and tetracarboxylate linkers with a planar core (NU-1101 through NU-1104) has been synthe-sized employing a linker expansion approach. In this series, NU-1103 has a pore volume of 2.91 cc g-1 and a geometrically calculated surface area of 5,646 m2 g-1, which is the highest value reported to date for a zirconium-based MOF, and among the largest that have been reported for any porous material. Success-ful activation of the MOFs was proven based on the agreement of pore volumes and BET areas obtained from simulated and experimental isotherms. Critical for practical applications, NU-1103 combines for the first time ultrahigh surface area and water stability, where this material retained complete structural in-tegrity after soaking in water. Pressure range selection for the BET calculations on these materials was guided by the four so-called "consistency criteria". The experimental BET area of NU-1103 was 6,550 m2/g. Insights obtained from molecular simulation suggest that, as a consequence of pore-filling contamina-tion, the BET method overestimates the monolayer loading of NU-1103 by ~16%.