A three-dimensional complex, [Mn-3(4-aba)(6)](n) (1) (4-Haba = 4-aminobenzoic acid), consisting of manganese(II) chains and 4-aba bridging ligands, has been synthesized and characterized. Magnetic studies show that the compound behaves as a three-dimensional metamagnet built of homometallic ferrimagnetic chains. The required noncompensation in spin moments is achieved by alternating interactions in an AF-AF-F sequence (AF = antiferromagnetic; F = ferromagnetic) by considering intrachain magnetic interactions.