Realizing the synthesis and crystal structure of microporous materials with pore sizes 10-20 Å has been a formidable challenge in molecular sieve science. Access to such materials, with uniform pore size, is expected to impact the petrochemical and the life-sciences fields by providing opportunities for the sizeand shape-selective catalysis/separation of large molecules.1 In this direction, theoretical approaches to decorating specific 4-connected networks have been proposed,2 whereby replacing each (T1) tetrahedron, TX4, in a given network by a larger tetrahedron (hereafter referred to as a supertetrahedron), signified Tn, yields a porous network due to the increased size of the building blocks.3 With large n, frameworks of unprecedented porosity could be achieved. Recognizing the potential of this approach, we have embarked on a program aimed at using inorganic clusters as molecular building blocks in the assembly of extended networks: The copolymerization of Mn(II) with the