Rigidity and stability, in addition to superior electronic, magnetic, and optical properties, have made inorganic frameworks highly attractive in the search for new, functional materials, 1 while organic and coordination compounds built upon molecular building-blocks hold great promises for processability, flexibility, structural diversity, and geometrical control, such as size, shape, and symmetry. 2 Incorporation of the two counterparts into a single structure may generate organic -inorganic hybrid composites that enhance or combine the useful properties of both components, as found in zeolites and other mesoporous oxides. 3 For example, an intensively pursued area in the miniaturization of electronic devices is the investigation of composite materials that combine the semiconducting functionality of the inorganic constituent with the lower weight and volume of the organic component. 1,4 Many examples have been reported in which organic species enter the inorganic structures through either ionic bonding or relatively weak H-bonding and van der Waals interactions. However, organic-inorganic covalent architectures with explicit bonding directions are much needed, but rare. 5 The novel periodic mesoporous organosilicas (PMOs) recently reported have shed light on the preparation of hybrid materials of this type. 6 The ability to change or modify physical properties, auch as optical absorption edges, is of equal significance to the synthesis of new materials. This can be achieved, for example, by controlling the alloy composition7 and the size of confined systems such as quantum dots (QD)8 and quantum well (QW). 9 Currently, semiconductor dots are preferred because a very large variation is achievable in these systems. 10 However, it is a great challenge to generate uniform and periodic lattices of dots. 11 Here, we report a new type of covalently bonded hybrid composites that not only possess a uniform and periodic structure, but simultaneously offer a significant variation of optical properties. The three novel compounds, [ R-ZnTe(en) 1/2] (I), [â-ZnTe(en) 1/2] (II ), and [ZnTe(pda) 1/2](III ), represent the first examples of chalcogenide-based hybrid materials of which uniform structures are formed via direct, covalent bonds between the inorganic host (the II-VI semiconductor ZnTe) and the organic spacers. I and II were synthesized in ethylenediamine (en) and III in 1,3propanediamine (pda). Both en and pda serve as solvents and as a source of bifunctional ligands. 12 I-III are stable in air for a long period of time. Upon heating they are converted to ZnTe by separating out the organic component, L. 12 The formation of the title compounds is, therefore, reversible: ZnTe + L (solvent)T ZnTe(L)1/2, L ) en, pda. The conversion between the two groups of compounds may also be achieved under mild conditions: ( I , II ) T III .12 X-ray diffraction analysis reveals that the crystal structure ofI is a three-dimensional network 13 containing 2D [ZnTe] slabs and en molecules, as illustrated in Figure 1a. The [ZnTe] slabs stack along the c-axis and are interconnected by en molecules, each bridged to two Zn metal centers from the adjacent slabs. As shown in Figure 1b, the inorganic slab is a puckered 6 3