Complexes [ZnfSe(2)P(OEt)(2)}(2)](infinity) (1) and [Zn-2{Se2P((OPr)-Pr-i)(2)}(4)] (2) are prepared from the reaction of Zn(ClO4)(2)(.)6H(2)O and (NH4)[Se2P(OR)(2)] (R = Et and Pr-i) in a molar ratio of 1:2 in deoxygenated water at room temperature. Positive FAB mass spectra show m/z peaks at 968.8 (Zn2L3+) and 344.8 (ZnL+) for 1 and m/z at 1052.8 (Zn2L3+) for 2. H-1 NMR spectra exhibit chemical shifts at delta 1.43 and 4.23 ppm for 1 and 1.41 and 4.87 ppm for 2 due to Et and Pr-i group of dsep ligands. While the solid-state structure of compound 1 is a one-dimensional polymer via symmetrically bridging dsep ligands, complex 2 in the crystalline state exists as a dimer. In both 1 and 2, zinc atoms are connected by two bridging dsep ligands with an additional chelating ligand at each zinc atom. The dsep ligands exhibit bimetallic biconnective (mu(2), eta(2)) and monometallic biconnective (eta(2)) coordination patterns. Thus, each zinc atom is coordinated by four selenium atoms from two bridging and one chelating dsep ligands and the geometry around zinc is distorted tetrahedral. The Zn-Se distances range between 2.422 and 2.524 Angstrom. From variable-temperature P-31 NMR studies it has been found that monomer and dimer of the complex are in equilibrium in solution via exchange of bridging and chelating ligands. However, at temperature above 40 degreesC the complex exists as a monomer and shows a very sharp peak while with lowering of the temperature the percentage of climer increases gradually at the expense of monomer. Below -90 degreesC the complex exists as a climer and two peaks are observed with equal intensities which are due to bridging and chelating ligands. Se-77 NMR spectra of both complexes at -30 degreesC exhibit three doublets due to the presence of monomer and dimer in solution.