NOVELTY - A porous metal-organic polyhedra (a1) comprises several of metal clusters (b1); capping ligands to inhibit polymerization of (a1); and several of multidentate linking ligands that connect adjacent (b1) into a geometrical shape such as polyhedron with (b1) positioned at least one vertices of the polyhedron. Each (b1) comprises at least two metal ions. The metal-organic polyhedron remains porous in the absence of a templating agent.    USE - In catalysis, gas sorption, separation and sensing applications.    ADVANTAGE - The metal-organic polyhedra (MOP) structures supports permanent porosity and exhibits type I isothermal behavior. The porous metal-organic polyhedra have a pore volume per gram of metal-organic polyhedra greater than 0.1 cm3/cm3.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) preparation of (a1) involving combining a solution comprising a solvent, at least one metal ions, and counterions that complex to (a1) as capping ligands to inhibit polymerization of the metal organic polyhedra, with a multidentate linking ligand having more than 16 atoms which are incorporated in aromatic rings; and    (2) method of designing (a1) involving selecting a first multidentate ligand of formula XnY (I); forming a first metal-organic polyhedra with the first multidentate ligand; measuring pore size or adsorption of a chemical species for the first metal-organic polyhedra; forming a second first metal-organic polyhedra from a second multidentate ligand. The second multidentate ligand having a larger number of atoms than the first multidentate ligand; measuring pore size or adsorption of a chemical species for the second metal-organic polyhedra; and iteratively forming alternative second multidentate ligands from alternative second ligands with increasing numbers of atoms until a predetermined pore size for adsorption of a chemical species is attained.    X = CO2-, CS2-, NO2 or SO3- (preferably CO2-);    n = at least 2;    Y = hydrocarbon group (optionally having at least one atoms replaced by a heteroatoms) (preferably 1-10C alkyl, 1-10C alkyl amine, 7-15C aryl amine, 7-15C aralkyl amine or 7-15C alkyl aryl amine).