A semirigid di-1,2,4-triazole ligand leads to formation of the MOF [Cu-2(L)(2)(SO4)(Br)(2))center dot xH(2)O (1). The framework structure of 1 flexes reversibly upon removal or addition of water to form semihydrated ([Cu-2(L)(2)(SO4)(Br)(2)]center dot 4H(2)O) and dehydrated ([Cu-2(L)(2)(SO4)(Br)(2)]center dot 0H(2)O) MOFs, 1' and 1 '', respectively. Single-crystal X-ray analysis demonstrated that the 2-butene subunit of the ligand rotates between two positions for 1 and 1', causing a change in the solvent. accessible volume in the framework. This double hinge within the semirigid ligand is a built-in breathing mechanism and suggests a novel approach for general synthesis of breathing MOFs.