Three new complexes {[Cu(L 1 ) 2 (NO 3 ) 2 ]·H 2 O} ¥ (1), {[Cu 4 (L 2 ) 2 (OAc) 8 ]×CH 3 CH 2 OH} ¥ (2) and [Cd 2 (L 3 ) 3 (NO 3 ) 4 (H 2 O) 2 ] ¥ (3) (L 1 = 4-phenyl-7-(pyridine-3-yl)-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole, L 2 = 4-(pyridine-3-yl)-7-phenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole, and L 3 = 4-(pyridine-4-yl)-7-phenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole) have been synthesized and characterized by elemental analyses, IR spectra and single crystal X-ray diffraction. The structural analyses reveal that complex 1 is a neutral 2-D network structure with a 4 4 topology, 2 has a 1-D neutral coordination chain with a [Cu 2 (CH 3 COO) 4 ] dinuclear structural unit bridged by four acetate ions, and 3 is a neutral rhombohedral grid structure. All the complexes are air stable at room temperature. Furthermore, the fluorescent properties of complex 3 and corresponding ligand L 3 have been investigated and discussed. Scheme 1 The structure of ligands L 1 -L 3 Scheme 2 The route of synthesis of ligands L 1 -L 3 CHEMICAL SOCIETY Fig. 1. View of (a) the coordination environment of Cu II ions in 1. (b) 2-D (4,4) network structure of 1 (H atoms are omitted for clarity). (c) 4 4 topology of 1. 790 www.jccs.wiley-vch.de