Conjugated polymers were developed by using thiophene-dione derivatives named DEHOB-BDTF and DBOOB-BDTF. The polymers have a combination of electron donor (D) and electron acceptor (A), in which 5-(3,4-bis(((2-ethylhexyl)oxy)benzylidene)-1,3-dibromo-4H-cyclopenta[c]thiophene-4,6(5H)-dione (DEHOB) or 5-(3,4-bis((2-butyloctyl)oxy)benzylidene)-1,3-dibromo-4H-cyclopenta[c]thiophene-4,6(5H)-dione (DBOOB) serves as the electron acceptor units. The alkoxy chain shows strong electron-donating properties due to conjugation effects while longer alkoxy chain increases the solubility. Non-fullerene PSCs are fabricated with an ITO/ZnO/polymer: Y6BO/MoO3/Ag structure in which Y6BO is used as an electron acceptor. The performance of the device by using DEHOB-BDTF is accomplished up to 8.49 % (an open-circuit voltage of 0.85 V and a short-circuit current density of 20.1 mA/cm2). Furthermore, the longer alkoxy chain length enhances solubility making a well-ordering in DBOOB and reaching the fill factor of 54.2 %, due to the extended alkoxy chain can improve the miscibility in the blend.