The reactions of bifunctional carboxylate ligands (1,8-naphthalimido)propanoate, (L-C2(-)), (1,8-naphthalimido)ethanoate, (L-C1(-)), and (1,8-naphthalimido)benzoate, (L-C4(-)) with Cu-2(O2CCH3)(4)(H2O)(2) in methanol or ethanol at room temperature lead to the formation of novel dimeric [Cu-2(L-C2)(4)(MeOH)(2)] (1), [Cu-2(L-C1)(4)(MeOH)(2)]center dot 2(CH2Cl2) (2), [Cu-2(L-C4)(4)(EtOH)(2)]center dot 2(CH2Cl2) (3) complexes. When the reaction of L-C1(-) with Cu-2(O2CCH3)(4)(H2O)(2) was carried out at -20 degrees C in the presence of pyridine, [Cu-2(L-C1)(4)(py)(4)]center dot(2)(CH2Cl2) (4) was produced. At the core of complexes 1-3 lies the square Cu-2(O2CR)(4) "paddlewheel" secondary building unit, where the two copper centers have a nearly square pyramidal geometry with methanol or ethanol occupying the axial coordination sites. Complex 4 contains a different type of dimeric core generated by two kappa(1)-bridging carboxylate ligands. Additionally, two terminal carboxylates and four trans situated pyridine molecules complete the coordination environment of the five-coordinate copper(II) centers. In all four compounds, robust pi center dot center dot center dot pi stacking interactions of the naphthalimide rings organize the dimeric units into two-dimensional sheets. These two-dimensional networks are organized into a three-dimensional architecture by two different noncovalent interactions: strong pi center dot center dot center dot pi stacking of the naphthalimide rings (also the pyridine rings for 4) in 1, 3, and 4, and intermolecular hydrogen bonding of the coordinated methanol or ethanol molecules in 1-3. Magnetic measurements show that the copper ions in the paddlewheel complexes 1-3 are strongly antiferromagnetically coupled with -J values ranging from 255 to 325 cm(-1), whereas the copper ions in 4 are only weakly antiferromagnetically coupled. Typical values of the zero-field splitting parameter D were found from EPR studies of 1-3 and the related known complexes [Cu-2(L-C2)(4)(py)(2)]center dot 2(CH2Cl2)center dot(CH3OH), [Cu-2(L-C3)(4)(py)(2)]center dot 2(CH2Cl2) and. [Cu-2(L-C3)(4)(bipy)]center dot(CH3OH)(2)center dot(CH2Cl2)(3.37) (L-C3(-) = (1,8-naphthalimido)butanoate)), while its abnormal magnitude in [Cu-2(L-C2)(4)(bipy)] was qualitatively rationalized by structural analysis and DFT calculations.