Organic solar cells (OSCs) have been attracting strong research interest as a promising clean renewable energy source due to their beneficial characteristics such as lightweight, mechanical flexibility, low cost, and solution processability. Herein, phenyl ester-based donor polymer (Ph-Ester-BTF) and [6]-phenyl C71-butyric acid methyl ester (PC71BM) acceptor was used as photoactive materials for the OSCs. With using Ph-Ester-BTF polymer as donor for OSCs, power conversion efficiency (PCE) was obtained as 2.68% for pristine chlorobenzene (CB) processed OSCs. Different solvents and additives were used for comparative study, wherein pristine CB yielded the better photovoltaic device performance of OSCs. Charge carrier mobility and film surface morphology was studied for further interpretation of the device performance.