Two complexes Cu(L)2(CH3COO)2 (1) and [Cu2(μ-CH3COO)4(L)2](L)2 (2) (L = N-(4′-methylaniline)-4-pyridinecarboxamide) have been prepared and their crystal structures have been determined by single-crystal X-ray diffraction. The complexes are obtained by using the same raw materials and reaction conditions except solvents. The presence or absence of water controls the coordination mode to give rise to different structures. The structure of 1 has a triclinic space group P-1 with a = 8.381(3) Å, b = 8.545(4) Å, c = 11.357(5) Å, α = 110.654(6)°, β = 102.388(7)°, γ = 97.889(7)°, V = 722.9(5) Å3, and Z = 1. The structure of 2 has a triclinic space group P-1 with a = 9.121(3) Å, b = 9.454(3) Å, c = 17.233(5) Å, α = 77.374(5)°, β = 89.827(6)°, γ = 74.342(6)°, V = 1393.8(7) Å3, and Z = 1. Supramolecular assemblies have also been found via noncovalent bonds such as hydrogen bonds, π–π stacking interactions.