Mayur Suri, Matthew Dornfeld, and Eric Ganz We have used accurate ab initio quantum chemistry calculations together with a simple model to study the hydrogen storage capacity of metal-organic and covalent-organic frameworks by spillover. Recent experiments by Tsao et al. [J. Am. Chem. Soc. 131, 1404 (2009)] {based on an earlier work by Li and ... [J. Chem. Phys. 131, 174703 (2009)] published Mon Nov 2, 2009.