Transient absorption measurement of radical anions of 1,1-diarylmethanols bearing electron-withdrawing groups in dimethyl-formamide at room temperature has revealed that symmetric compounds form intramolecular dimer radical anions as an intermediate of their reductive C-O bond dissociation giving diarylmethyl radicals. The dimer radical. anions showed an absorption band in the near infrared region (NIR) (1000-1600 nm) characteristic to their charge resonance (CR) properties. On the contrary to 1, 1-diarylmethanols, corresponding radical anion of 1,3-diarylpropan-1-ol showed no CR band. It is suggested that formation of dimer radical anions is energetically favorable for diaryl compounds with one-atom spacer but unfavorable for them with three-atom spacer being different From the n = 3 rule for the favorable formation of intramolecular excimers.