Photoinduced electron transfer (PET) with the formation of stable radicals plays an importance role in many areas. However, the discovery of new photoresponsive moieties is still a challenge. In this work, pyridine N-oxide group itself was demonstrated to possess photoinduced electron transfer (PET) property for the first time. The radical of 4-phenyl-pyridine-N-oxide (ppno), generated by PET from oxygen atom to 4-phenyl-pyridine part, remained stable in dark in air at least for two weeks. [ZnCl2(ppno)2], one ppno-based novel crystalline coordination compound, has two electron donors, chlorine and oxygen atoms. In particular, experimental and theoretical calculation results showed that oxygen atoms in [ZnCl2(ppno)2] have dual actions. Firstly, oxygen atom as electron-withdrawing group increased the electron accepting ability of 4-phenyl-pyridine. Then, oxygen atoms themselves are rich in electrons and can act as electron donors. This is exactly why the performance of PET and radical yield and stability of [ZnCl2(ppno)2] much better than ppno. Thus, pyridine N-oxide group as an effective photoresponsive functional motif, whether by interspersion or by coordination, could construct various novel photoresponsive materials.