Benzodithiophene based organic semiconducting polymer was designed and synthesized by stille coupling reaction. The structure of polymer was confirmed by NMR and IR. The weight average molecular weight ($M_w$) of polymer was 8,400 using GPC with polydispersity index of 1.4. The thermal, optical and electrochemical properties of polymer were characterized by TGA and DSC, UV-vis absorption and cyclic voltammetry. OTFT device using PBDT-10 exhibited the mobility of $7.2{ imes}10^{-5};cm^2;V^{-1};s^{-1}$ and $I_{on}/I_{off}$ of $2.41{ imes}10^3$. The film morphology and crystallinity of PBDT-10, was studied using AFM and XRD.