The key to soc-cess: The trimer building block [In3O(CO2)6] and a tetracarboxylate organic linker assemble into a novel porous metal–organic framework (see picture; In green, C gray, N blue, O red; cavity: yellow sphere) having an unprecedented soc topology (soc=square–octahedron) and high H2 uptake. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z604306_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.