This report deals with a study of the incorporation of an amphiphilic polydiacetylene, poly(PCDA) in a polymer bulk heterojunction solar cell with MEH-PPV. A poly(PCDA) inserted layer was prepared by spin-coating a poly(PCDA) solution on PEDOT:PSS/ITO coated glass slide. The solar cells structure was completed by spin-coating MEH-PPV solution and Al sputtering, respectively, on top to form ITO/PEDOT:PSS/PDA/MEH-PPV/Al structure. Comparing to the device without poly(PCDA) layer, the current density–voltage characteristics of the device with poly(PCDA) showed an increase of the power conversion efficiency from 0.00035 to 0.00057%, fill factor from 0.18 to 0.19, open circuit voltage from 0.93 to 1.02 V and short-circuit current density from 0.0021 to 0.0029 mA/cm2 under Air Mass 1.5 simulated solar illumination (100 mW cm−2). The surface morphology of the poly(PCDA) layer studied by AFM imaging revealed that the pre-coated layer of PEDOT:PSS layer improved the roughness and surface coverage of poly(PCDA) on the silicon wafer. Cyclic voltametry gave the HOMO and the LUMO of poly(PCDA) of −5.9 and −4.1 eV, respectively. UV–Vis absorption spectroscopy of poly(PCDA) film showed the absorption band in the range of 500–750 nm with the maximum absorption at around 680 nm.