Synthesis of new small molecule based on Quinoxaline and Thienothiophene (TT) or bi-thiophene (bi-T) having low-lying highest occupied molecular orbital (HOMO) was implemented for organic solar cells. These small molecule showed absorption in the range of 426 nm ~ 495 nm in chloloform (CF) solution state. In film state, absorption spectra of small molecule showed 30 nm ~ 40 nm red shift compared to in solution state. These small molecules were observed an optical band gap of 1.93 ~ 2.40 eV. In cyclic voltammetry, HOMO and LUMO range of (-5.20 ~ 5.32) and (-2.92 ~ -3.39). especially, 3TDFQx (In), 3TDFQx (Out) and T-TT-DFQx (In), T-TT-DFQx (Out), orientation of side chain affected electrochemical, optical and finally photovolataic properties. The material with side chain outward had more shift absorption spectra and deeper HOMO level than those with inward. In conclusion, material with side chain outward had better Jsc, Voc and PCE.