To explore the relationships between the structures of ligands and their complexes, we have synthesized and characterized a series of metal complexes with two structurally related ligands, 9-acridinecarboxylic acid (HL1) and 4-quinolinecarboxylate acid (HL2), [Cu-2(mu(2)-OMe)2(L-1)2(H2O)(0.69)](n) 1, [Cu-2(L-1)(4)(CH3OH)(2)] 2, [Cu-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 3, [Mn-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 4, [Co-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 5, [Cu(L-2)(2)], 6, [Mn(L-2)(2)(H2O)](n) 7, and [Co(L-2)(2)(H2O)](n) 8. 1 is a three-dimensional (3D) polymer with an interpenetrating NbO type network showing one-dimensional (1 D) channels, whereas 2 and 3 take bi- and trinuclear structures, respectively, because of the differences in basicity of the reaction systems in preparing the three complexes. 4 and 5 have trinuclear structures similar to that of 3. In 1-5, ligand L-1 performs different coordination modes with NO-bridging in 1 and O,O'-bridging in 2-5, and the metal ions also show different coordination geometries: square planar in 1, square pyramidal in 2, and octahedral in 3-5. 6 has a two-dimensional structure containing (4,4) grids in which L-2 adopts the NO-bridging mode and the Cull center takes square planar geometry. 7 and 8 are isostructural complexes showing 1 D chain structures, with L-2 adopting the O,O-bridging mode. In addition, the intermolecular O-H center dot center dot center dot N hydrogen bonds and pi-pi stacking interactions further extend the complexes (except 1 and 6), forming 3D structures. The magnetic properties of 2-7 have been investigated and discussed in detail.