Synthetic polypeptides with rigid α-helical structure are regarded as promising materials for molecularly ordered membrane with high charge or energy transport properties. We prepared Ru (bpy) ₃²⁺/α-helical poly (L-glutamic acid) (PGA) complex to study charge transport properties and its application to optoelectric devices. Substitution ratio of long alkyl chain group and polypeptide secondary structures were characterized by ¹H-NMR and IR spectra. The interaction between PGA and Ru (bpy) ₃²⁺ was analyzed with CD and fluorescence spectroscopy. The structure of PGA/Ru (bpy) ₃²⁺ complex was estimated. Further, we prepared EL device with PGA/ Ru (bpy) ₃²⁺ complex to discuss the emission mechanism.