Novel polynuclear Cu(II) complexes containing derivatives of 1,2,4-trizaole and pivalate ligands, [Cu-3(mu(3)-OH)(mu-adetrz)(2)(piv)(5)(H2O)center dot 6.5H(2)O (1) (adetrz = 4-amino-3,5-diethyl-1,2,4-triazole, piv = pivalate), [Cu-4(mu(3)-OH)(2)-(mu-atrz)(2)(mu-piv)(4)(piv)(2)]center dot 2MeOH center dot H2O (2) (atrz = 4-amino-1,2,4-triazole), [Cu-4(mu(3)-OH)(2)(mu-tbtrz)(2)(mu-piv)(2)(piv)(4)]center dot 4H(2)O (3) (tbtrz = 4-tert-butyl-1,2,4-trizaole), and [Cu-4(mu(3)-O)(2)(mu-admtrz)(4)(admtrz)(2)(mu-piv)(2)(piv)(2)]center dot 2[Cu-2(mu-H2O)(mu-admtrz)(piv)(4)]center dot 13H(2)O [4 = 4a(.)2(4b)(.)13H(2)O; admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole], have been prepared and structurally characterized. 1 is an asymmetrical triangular complex containing a [Cu-3(mu(3)-OH)] core with two Cu---Cu edges spanned by bridging adetrz ligands. 2, 3, and 4a are novel tetranuclear compounds containing a [Cu-4(mu(3)-O)(2)] or [Cu-4(mu(3)-OH)(2)] core with Cu---Cu edges spanned by bridging 1,2,4-triazole or pivalate ligands. 0 is a dinuclear compound with one admtrz and one water bridge, and it is the first dinuclear Cu(II) triazole complex with one bridging water molecule. 1 is one of few reported triangular Cu(II) complexes with derivatives of 1,2,4-triazole, while 2, 3, and 4a are the first group of the nonlinear tetranuclear Cu(II) compounds with derivatives of 1,2,4- triazole. Variable-temperature magnetic susceptibility studies on the powder samples of 1-3 reveal the overall antiferromagnetic coupling between Cull ions with J values of -55.6 to -12.8 cm(-1) (1), -216.4 to 0 cm(-1) (2), and -259.8 to 4.8 cm(-1) (3).