A metal-organic framework (MOF) built from two organic linker groups instead of the usual one provides strong evidence that surface area alone may not be an indicator of these materials' hydrogen storage ability. Just over a year ago, Adam J. Matzger's group at the University of Michigan added a twist to making MOFs, which are being explored for gas storage, catalysis, and chemical separation applications. By combining zinc with two different types of commonly used organic linker groups, the researchers built a novel zinc coordination copolymer, UMCM-1, with a record surface area for a mesoporous channel material of 4,160 m2/g and properties that surpass those of the materials made by using either one of the organic linkers alone. Now, Matzger and coworkers have used a different combination of linker groups to create the second such coordination copolymer (J. Am. Chem. Soc., DOI: 10.1021/ja809985t). Dubbed UMCM-2, Matzger's new MOF has a strikingly different structure from its predecessor and sets a new surface-area record of 5,200 m2/g. The hydrogen-storage capacity of UMCM-2 is not any better than related MOFs, however, suggesting that surface area alone is not predictive of hydrogen uptake, Matzger says.