A mesostructured chalcogenide built from Chevrel-type clusters [(Re6Se6Br2)Br6T](2-) linked by ditopic [Se-3](2-) anions and synthesized in the presence of a cationic surfactant template is reported. This new mesophase, h-C18PyReSeBr, exhibits remarkably well ordered hexagonal symmetry from which a reasonable structural model can be deduced on the basis of powder X-ray diffraction as well as pair distribution function (PDF) analysis. Small-angle X-ray scattering (SAXS) analysis shows that h-C18PyReSeBr possesses an enormous interfacial area of 477 m(2)/g between the inorganic framework and the guest surfactant cations, which is comparable to that of mesoporous silicas when heavy metals contained in the framework are taken into consideration. The framework of h-C18PyReSeBr exhibits great flexibility and responds dynamically to the extraframework cations via an ion-exchange process.