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Six new metal–organic frameworks (MOFs), namely,[Pb(H2IDC)2(H2O)]n(1), {[Pb(H2IEDC)2)]·3H2O}n(2), [Ca2(HIDC)2(H2O)]n(3), {[Ca2(IEDC)2(H2O)2]·H2O}n(4), {[Cd(HIDC)(H2O)]n(5), and {[Cd2(HIEDC)2·3H2O}n(6) (H3IDC = 4,5-imidazoledicarboxylic acid, H3IEDC = 2-ethyl-1H-imidazole-4,5-dicarboxylicacid) were hydrothermally synthesized and characterized. Single-crystalX-ray diffraction shows the ligand H3IDC is partially deprotonatedwith H2IDC–and HIDC2–forms in three corresponding compounds 1, 3, and 5, meanwhile ligand H3IEDC also presentsdifferent deportonated motifs of H2IEDC–, IEDC3–, and HIEDC2–in 2, 4, and 6, respectively. Moreover,these partially or fully deportonated ligands coordinate in the μ1to μ5manner to generate one-dimensional(1D) → three-dimensional (3D) coordination polymers, displaying10 different coordination modes. Both 1and 2have 3D supramolecular networks assembled via hydrogen bonding interactionsbut different in structure topologies. Complex 1is a1D coordination chain and 2has a two-dimensional (2D)wave layer-like structure with 44topology. Complex 3is a 3D MOF with 310·425·510topology built up from linear 2-connected HIDC2–as a linker and 10-connected tetranuclear metal unit [Ca4(μ2-O)6] as a node. However, complex 4presents a 2D MOF with 36·46·53topology. Different from 3and 4, with the 4-connected binuclear metal unit [Cd(O–C–O)]2as a node, a wave-like 2D MOF with 44topologyin 5based on H3IDC is created. Complex 6shows a 3D coordination framework containing 1D alternatelyarranged hydrophilic channels including (H2O)4clusters and hydrophobic channels partially occupied by ethyl groupsfrom imidazole rings, in which the Cd(II) ion is viewed as a 4-connectednode, and HIEDC2–and μ2-O areregarded as two different linkers, 6showing 42·84topology. Obviously, these results reveal thatthe existence of the substitute groups of 2-position in such 4,5-imidazoledicarboxylateligand plays a critical role in the structural direction of theseMOFs. Meanwhile, the adsorption and photoluminescent properties ofthe selected compounds are investigated. [ABSTRACT FROM AUTHOR]