(Quinolinium)₂CuBr₄*2H₂O (1) crystallizes in the monoclinic space group C2/C with a = 12.3323(7)Å, b = 9.7972(6)Å, c = 18.6504(11)Å, α = 100.3220(10)°, V = 2216.9(2). Layers of CuBr₄^2- tetrahedra are separated by layers of quinolinium cations; N-H…H-O-H…Br-Cu hydrogen bonding tie the layers together. Additionally, O-H…Br hydrogen bonding between CuBr₄^2- tetrahedra forces close Br…Br contacts, forming a 2-D magnetic layer. Field dependent magnetic behavior shows upward curvature, typical of a low-dimensional system. A fit to the temperature dependent susceptibility 2-D Heisenberg model gives J/k_b ~ 6K. Upon heating to ~325K, a structural phase transition to the anhydrous phase (Quinolinium)₂CuBr₄ (2) occurs. Compound 2 crystallizes in the triclinic space group P-1 with a = 7.6738(15)Å, b = 8.9490(18)Å, c = 16.325(3)Å, α = 78.71(3)°, β = 83.45(3)°, γ = 71.74(3)°, V = 1042.4(4)ų. As a consequence, close Br…Br contacts still exists, although with much different Cu-Br…Br-Cu angles. Temperature dependent susceptibility data does not show any significant interactions down to 1.8K.