A bifunctional organic linker 4-(4-carboxyphenyl)-1,2,4-triazole (HCPT), incorporating both carboxylate and triazole groups,, has been,successfully used in the construction of a 2-fold interpenetrated dynamic metal organic framework (MOF), {[Cu-3(CPT)(4)(mu(3)-OHN)]center dot NO3 center dot 7H(2)O center dot EtOH}(n) (1) based on a triangular Cu(II)-hydroxo cluster as secondary building unit (SBU). Upon solvation/desolvation and temperature, the crystal cell parameters of 1 Could be fine-tuned. More importantly, a transformation from disordered phase to a more ordered phase after activation was observed via a single-crystal-to-single-crystal mode. Gag sorption studies reveal that the activated 1 exhibits highly selective sorption of CO2 over N-2 CH4 at room temperature.