The solvothermal cycloreversion and in situ oxidation of 1,2,3,4-tetra(pyridin-4-yl)cyclobutane (tpcb) within [CuCN](n)-based MOFs were investigated. The radical mechanism for the cycloreversion of tpcb ligands was supported by capturing a 1,3-butadiene species 1,2,3,4-tetra(4-pyridyl)-1,3-butadiene (tpyb) into {[Cu-18(mu-CN)(18)(tpcb)(4)(tpyb)(2)]center dot H2O}(n) in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Without TEMPO, a furan-based ligand 2,3,4,5-tetra(4-pyridyl)-furan (tpyf) was generated within {[Cu-4(mu-CN)(4)(tpyf)]center dot 4MeCN}(n) via the C-C cleavage, followed by in situ oxidation in acidic condition.