The authors develop organic solar cells (OSCs) with a multicharge separation (MCS) interface by inserting ∼4 nm thin layer of phosphorescent bis(2-(4-tertbutylphenyl) benzothiazolato-N,C2,) iridium (acetylacetonate) (t-bt)2Ir(acac) comparing with copper phthalocyanine (CuPc) between pentacene/C60 heterojunction. The result showed that open circuit voltage is remarkably enhanced without obviously changing external quantum efficiency ηEQE and short-circuit current density. As a result, power conversion efficiency is improved from 1.53% for pentacene/C60 device to 1.83% with sandwich layer (t-bt)2Ir(acac) and 1.98% with CuPc. Moreover, a suitable equivalent circuit model is proposed to intuitively reveal the inner photogeneration process of OSC with MCS interface.