The metal-organic framework Cu-I-MFU-4l reacts with NO, initially forming a copper(I)-nitrosyl at low pressure, and subsequently generates NO disproportionation products Cu-II-NO2 and N2O. The thermal stability of MFU-4l allows NOx to be released from the framework at temperatures greater than 200 degrees C. This treatment regenerates the original Cu-I-MFU-4l, which can engage in subsequent cycles of NO disproportionation.