Two new nickel nitrates, diaquabis(3,4,7,8-tetramethyl-1,10-phenanthroline-κ²N,N′)nickel(II) dinitrate methanol solvate, [Ni(C₁₆H₁₆N₂)₂(H₂O)₂](NO₃)₂·CH₄O, (I), and triaqua[2,4,6-tris(2-pyridyl)-1,3,5-triazine-κ³N¹,N²,N⁶]nickel(II) dinitrate trihydrate, [Ni(C₁₈H₁₂N₆)(H₂O)₃](NO₃)₂·3H₂O, (II), are reported. In both structures, the cation is octahedrally coordinated, to two bidentate 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp) and two water molecules in (I), and to one tridentate 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tpt) and three water molecules in (II). Both structures are stabilized by extensive hydrogen-bonding interactions.