A mesoporous metal-organic framework Cu-3(PTB)(2)(H2O)(3) center dot guest (denoted as SUMOF-5) has been synthesized using a new tritopic linker pyridine-2,4,6-tribenzoic acid (H3PTB). SUMOF-5 is cubic with the space group Fm (3) over barm and a = 47.272(3) angstrom. The framework is built of the dicopper paddle-wheel secondary building unit (SBU) [Cu-2(OOC)(4)(H2O)(2)] and contains two different cavities of 1.22 and 2.33 nm in diameter, respectively. The framework topology follows the (3,4)-connected tbo net, and can be regarded as an extended version of Cu-3(BTC)(2)(H2O)(3) center dot guest (HKUST-1, BTC = benzene tricarboxylate). The structure of SUMOF-5 is compared to other MOFs built from dicopper paddle-wheels and tritopic linkers. SUMOF-5 has permanent porosity with a Langmuir surface area of 1733 m(2)/g and is stable in various organic solvents, which makes this material potentially useful as a crystalline carrier for loading molecular catalysts or drugs.