We demonstrate the one-pot synthesis of highly porous crystalline metal−organic frameworks, [Zn<sub>4</sub>O(piperazine dicarbamate)<sub>3</sub>], an analogue of [Zn<sub>4</sub>O(1,4-benzenedicarboxylate)<sub>3</sub>] (MOF-5), directly from atmospheric pressure CO<sub>2</sub> gas and piperazine derivatives at 25 °C. The structures showed high CO<sub>2</sub> contents over 30 wt% and surface areas of 1270−2366 m<sup>2</sup> g<sup>−1</sup>. We also show that the synthesis is feasible even by the use of 400 ppm of CO<sub>2</sub>.