The mixed-valence state for (S,S), (R,R), and DL samples in l',l"'bis(2-phenylbutyl)-l,l"'-biferrocenium salt was investigated and compared with that in l',l"'-bis(2-methylbutyl)-1,1"-biferrocenium triiodide. The difference between them was attributed to the effect of benzene ring. It was understood that the packing effect becomes more substantial by introducing the benzene ring in the substituent.