The coordination polymers {[CU3(TMA)(2)(Im)(6)(H2O)]* 7H(2)O}n (1) and {[CU3(TMA)(2)(Me-IM)(6)(H2O)]*16H(2)O}(n) (2) were synthesized by combining copper sulfate, TMA, and either Im or Me-Im in water. Single-crystal X-ray diffraction studies revealed that both compounds are composed of 2D sheets of Cu2+ cations and TMA(3-) anions. Hydrogen bonding between sheets in 1 stabilizes its 3D structure, while 2 is destabilized because of the absence of intersheet hydrogen bonding.