New type of polyethylene imine having butyl (-C4H9) substituent azobenzene side chain group through methylene spacer group (PEI64) was successfully synthesized by solution polycondensation reaction. Synthesized polymer was characterized by DSC, Polarized Optical Microscopic and X-ray diffraction analysis. The effect of reaction parameters on degree of substitution of PEI64 also studied and optimized the reaction conditions. Synthesized polymer possessed liquid crystalline (LC) properties. Photochemical, thermooptical as well as photoorientational behavior of the polymer were investigated elaborately. Spin coated PEI64 film showed out-of-plane molecular orientation on annealing. PEI64 both in solution and in solid film exhibited photoresponsive properties upon irradiation of UV and visible light. PEI64 film also exhibited reversible molecular orientation from random state to out-of-plane and from out-of-plane to random state on annealing, non-polarized UV and visible light irradiation.