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Six Zn­(II) coordination polymers, [Zn­(H2L)­(Hipa-CH3)2]·2H2O (1), [Zn2(HL)2(ipa-CH3)] (2), [Zn2(HL)2(ipa-NO2)]·2H2O (3), [Zn2(HL)2(ipa-NO2)] (4), [Zn2(HL)­(BTCA)­(H2O)]·H2O (5), and [Zn3(HL)3(BTCA)] (6), were synthesized by reactions of Zn­(II) salts with rigid ligand 1-(1H-imidazol-4-yl)-4-(4H-tetrazol-5-yl)­benzene (H2L) and different carboxylic acids, 5-methyl-isophthalic acid (H2ipa-CH3), 5-nitro-isophthalic acid (H2ipa-NO2), and 1,2,4-benzenetricarboxylic acid (H3BTCA). Complexes 1 and 2 were formed under different pH values, and 1 is a one-dimensional (1D) chain extended by hydrogen bonds and π–π stacking interactions to form a three-dimensional (3D) supramolecular polymer, while 2 exhibits a uninodal 6-connected 3D architecture with (412·63)-pcu topology based on the binuclear Zn­(II) secondary building units (SBUs). Polymers 3 and 4 present a pair of pseudopolymorphs with layered-pillared framework. Polymer 3 possesses Zn2(HL–)2 2+ sheets pillared by the ipa-NO2 2– ligand to form a 3D net, while 4 builds on the [Zn2(HL)­(ipa-NO2)]+ layer pillared by HL– ligand. Complex 5 is a (3,8)-connected tfz-d 3D net with point (Schläfli) symbol (43)2(46·618·84) based on the tetranuclear [Zn4(COO)4] SBUs, while the BTCA3– ligands act as three-connector pillars to link adjacent [Zn3(HL–)3]3– layers into a 3D net for 6. Complexes 1–6 exhibit intense light blue emission in the solid state at room temperature, and activated sample 6 shows highly selective CO2 uptake over N2 and H2.

The elaborately designed π-electron-rich fluorescent ligand 1,4-bis(1-carboxymethylene-4-imidazolyl)benzene (H 2 L), possessing bifunctional groups including the carboxylate groups (building units) and 4-imidazoyl groups (N-donor potential active sites) has been employed to construct fluorescent coordination polymers. A luminescent sensor, namely [Cd(L)(phen) 2 ]•5H 2 O (1), was obtained, which has a one-dimensional structure. The fluorescent material shows a blue emission maximum at 457 nm with a luminescence lifetime of 488 ns and a quantum yield (QY) of 4.56%. Significantly, 1 serves as a promising multiresponsive luminescent sensor to detect trace nitroaromatic compounds (NACs) with the limits of detection (LOD) of 7.21 × 10 −8 , 1.85 × 10 −5 , and 1.15 × 10 −5 mol/L for 2nitrophenol (2-NP), 3-nitrophenol (3-NP), and 4-nitrophenol (4-NP), respectively. Furthermore, CP 1 exhibits fluorescent turn-off and turn-on sensing behavior for Fe 3+ and Al 3+ metal ions with trace amounts of 1.05 × 10 −7 and 1.13 × 10 −7 mol/L, respectively. Experimental methods and theoretical calculations were employed to elucidate the sensing mechanism in detail.