The products of the reactions of copper(II) starting materials with 4-pyridyltetrazole (4-Hpt) in N,N-dimethylformamide (DMF)/methanol solutions are determined by the anion identity and concentration. In the absence of chloride, the 3-D open-framework material [Cu-3(OH)(3)(4-pt)(3)(DMF)(4)] center dot 5DMF center dot 3MeOH (1 center dot 5DMF center dot 3MeOH) is isolated, while variations in the chloride concentration yield the 2-D and 3-D materials, 2 and 3, respectively. All three structures exhibit trinuclear copper(II) building blocks: the triangular {Cu3(mu(3)-OH)}(5+) core in 1 and {Cu3Cl4(4-pt)(4)(4-Hpt)(2)}(2-) and {Cu3Cl2(4-pt)(8)}(4-) chains in 2 and 3, respectively. All three materials display microporosity, which is highly dependent on the method of sample preparation.