Three coordination polymers, namely, {[Co(L 1 )(HBTC)]•0.5L 1 , have been synthesized based on three semi-rigid nitrogen-containing ligands (L 1 = 4,4'-(2,5-dimethoxy-1,4-phenylene)dipyridine; L 2 = 4,4'-(2,5-diethoxy-1,4-phenylene)dipyridine; L 3 = 4,4'-(2,5-dibutoxy-1,4-phenylene)dipyridine) and 1,3,5-benzenetricarboxylic acid (H 3 BTC). Both I and II are a 4-connected uninodal sql net with point symbol {4 4 •6 2 }, III is a 6-connected uninodal rob net with point symbol {4 8 •6 6 •8}. The complexes were characterized by X-ray single-crystal diffraction (CIF files CCDC nos. 2034103 (II), 2034104 (III)), PXRD, IR spectra and TGA. Interestingly, the structural diversity of these complexes derived from the length of substituents on L n (n = 1, 2, 3) ligands.