A discrete dicopper(II) system, [Cu(bipy)(H(2)mpba)](2)center dot 2H(2)O (1), and its isomeric chain, [Cu(bipy)(H(2)mpba)]center dot dmso (2) [bipy = 2,2'-bipyridine and H(4)mpba = N, N'-1,3-phenylenebis(oxamicacid)], were obtained by modifying the ratio of the H2O-dmso solvent mixture, and their interconversion was also monitored by changing the solvents during the synthesis. The solvents play an essential role in the formation and crystallization of these complexes, presenting different dimensionalities and connectivities. The double deprotonated H(2)mpba(2-) adopts the bidentate/monodentate (1) and bis-bidentate (2) bridging modes toward the (2,2'-bipyridyl) copper(II) units affording a dinuclear compound (1) and a linear chain (2), respectively. Variable-temperature magnetic measurements show the occurrence of weak intradinuclear (1) and intrachain (2) antiferromagnetic interactions.