The objective of this paper is to compare the influence of two electron-withdrawing groups (-CN and-NO2) in the fragmentation of 2-methoxy-4-nitrophenyl benzyl ether and 4-cyanophenyl benzyl ether once these species are reduced. The stability of the corresponding radical anions depends essentially on those substituents. In our design we have chosen two species that are able to attach the electron but which have each a different capacity to retain it. An experimental study is carried out by EPR spectroscopy to analyze the different electronic nature of the generated radical anions. In addition, electronic structure calculations at the DFT level of theory have been performed to study those radical anions and their fragmentation pathways. The thermodynamics and kinetics of the two fragmentations are discussed and compared in detail.