Starting from the same metal salts and mixed organic ligands of 1,3,5-tris(1-imidazolyl)benzene (tib) and 2-bromo-1,4-benzenedicarboxylic acid (H2BDC-Br), two novel zinc(II) coordination polymers [Zn2(tib)2(BDC-Br)]2·2SO4·17H2O (1) and [Zn4(tib)2(BDC-Br)3(H2O)4SO4]·7.5H2O·2.5DMF (2) (DMF = N,N-dimethylformamide) were obtained by using different solvent systems of DMF/H2O and DMF/EtOH/H2O, respectively. 1 is an unusual (3,4)-connected 3D net with a Point symbol of {4·8·10(4)}{4·8·10}, while 2 is a complicated 1D chain, which is further connected to form a 3D supramolecular architecture by hydrogen bonding interactions. In particular, 1 and 2 exhibit selective adsorption of CO2 over N2 and show good selectivity for detection of acetone via fluorescence quenching.