Two new Ni^II complexes involving the ancillary ligand bis[(pyridin-2-yl)methyl]amine (bpma) and two different carboxylate ligands, i.e. homophthalate [hph; systematic name: 2-(2-carboxylatophenyl)acetate] and benzene-1,2,4,5-tetracarboxylate (btc), namely catena-poly[[aqua{bis[(pyridin-2-yl)methyl]amine-κ³N,N′,N″}nickel(II)]-μ-2-(2-carboxylatophenyl)aceteto-κ²O:O′], [Ni(C₉H₆O₄)(C₁₂H₁₃N₃)(H₂O)]_n, and (μ-benzene-1,2,4,5-tetracarboxylato-κ⁴O¹,O²:O⁴,O⁵)bis(aqua{bis[(pyridin-2-yl)methyl]amine-κ³N,N′,N″}nickel(II)) bis(triaqua{bis[(pyridin-2-yl)methyl]amine-κ³N,N′,N″}nickel(II)) benzene-1,2,4,5-tetracarboxylate hexahydrate, [Ni₂(C₁₀H₂O₈)(C₁₂H₁₃N₃)₂(H₂O)₂]·[Ni(C₁₂H₁₃N₃)(H₂O)₃]₂(C₁₀H₂O₈)·6H₂O, (II), are presented. Compound (I) is a one-dimensional polymer with hph acting as a bridging ligand and with the chains linked by weak C–H⋯O interactions. The structure of compound (II) is much more complex, with two independent Ni^II centres having different environments, one of them as part of centrosymmetric [Ni(bpma)(H₂O)]₂(btc) dinuclear complexes and the other in mononuclear [Ni(bpma)(H₂O)₃]²⁺ cations which (in a 2:1 ratio) provide charge balance for btc^4- anions. A profuse hydrogen-bonding scheme, where both coordinated and crystal water molecules play a crucial role, provides the supramolecular linkage of the different groups.