The syntheses, characterizations and structures of a neutral 2D coordination polymer [Cd(bnzd)(NCS)₂]n (1) and a polycationic 3D coordination polymer isolated as perchlorate salt [Cd(bnzd)₃]n(ClO₄)₂n (2) (bnzd = benzidine) are described. X-ray structural analyses reveal that each hexacoordinated cadmium(II) center in 1 adopts a distorted octahedral geometry with a CdN₄S₂ chromophore bound by two N atoms of two different bnzd units and two N and two S atoms of symmetric doubly bridged end-toend NCS− units extended in a 2D sheet. Six N atoms of six different bridged bnzd units are bonded to each cadmium(II) in 2 in a non-ended fashion affording a 3D network structure. In the crystalline state, each 2D sheet structure in 1 is further stabilized by π· · ·π interaction which in turn affords a 3D network structure through multiple intermolecular N-H· · · S hydrogen bonds. On the other hand, the 3D network structure in 2 is stabilized by weak intermolecular N-H· · ·O hydrogen bonds and C-H· · ·π interactions. Bnzd, 1 and 2 display intraligand 1(π-π*) fluorescence in DMF solution at room temperature.

A neutral coordination polymer of chloridomercury(II) of the type[Hg(bzpy).μ−Cl/Cl]_n (1) and a dinuclear complex of bromidomercury(II) of the type [Hg(bzpy).μ − Br/ Br]₂ (2) (bzpy = 2-benzoylpyridine) were synthesized using a 1:1 molar ratio of HgCl₂/HgBr₂ and bzpy in methanolic solvent at room temperature and X-ray crystallographically characterized. Structural analyses show that each mercury(II) center in both the compounds adopts a distorted square pyramidal geometry with an HgNOX₃ [X = Cl in 1 and X = Br in 2] chromophore. Each mercury(II) center in the coordination polymer 1 is connected to two other metal(II) centers through two different chlorido bridges affording a zigzag one-dimensional (1D) chain. In the crystalline state, 1D chains in 1 are stabilized through weak non-covalent C−H···π interactions promoting to a 2D sheet structure,and these 2D sheets, in turn, are further associated through intermolecular C−H···O hydrogen bonds resulting in a 3D network structure. In 2, two bromide ions bridge two metal(II) centers to form a dinuclear entity. Thedinuclear units in 2 are packed through π · ·π stacking and intermolecular C−H · ·O hydrogen bonds to afford a 2D sheet structure. These 2D sheets self-assemble through intermolecular C−H···Br hydrogen bonds promoting to a 3D network structure. The thermally stable compounds 1 and 2 exhibit intraligand 1

¹(π−π^*)/fluorescence in DMF solutions at room temperature