Photolysis of tetraphenylacetone on LZ-105 zeolites leads to diphenylmethyl radicals. Diffuse reflectance laser flash photolysis showed that most of the radicals decayed in the microsecond time scale. However, approximately 2-7% of the diphenylmethyl radicals remained as persistent radicals probably inside the zeolite channels with lifetimes of the order of weeks. The persistent radicals were detected by steady-state diffuse reflectance and steady-stale and time-resolved fluorescence spectroscopy. In addition to the diphenylmethyl radicals, stable diphenylmethyl carbocations were formed and were detected by steady-state diffuse reflectance and steady-state and time-resolved fluorescence spectroscopy.