Poly(ethersulfone)s carrying pendant imide side group with a low dielectric constant were prepared. The first step in the preparation involved the nitration of poly(ethersulfone) ($ultrason^{(R)}$-S6010), with ammonium nitrate and trifluoroacetic anhydride resulting in the nitrated poly(ethersulfone) ($NO_2$-PES). In the second step, the nitro groups on the polymer reacted with tin(II)chloride and sodium iodide as reducing agents for creating the amino poly(ethersulfone) ($NH_2$-PES). The imide-poly(ethersulfone)s (IPES) were obtained by a reaction of phthalic anhydride and amino poly(ethersulfone) with triethyl amine. The different degrees of imide units of poly(ethersulfone) were synthesized successfully under optimized condition. The IPES were studied by FTIR, $^1H$ NMR spectroscopy, differential scanning calorimetry (DSC), and thermo gravimetric analysis (TGA). The optical and electrical properties of IPES were comparable to PES rather than PI. The slightly decreased birefringence and dielectric constant of IPES might originate from the reduced packing of polymer chains due to the presence of bulky imide pendent groups.