Linear green light-emitting electro-phosphorescent polymers have been successfully developed by chemically attaching a benzoimidazole-based iridium complex to the side chain of poly(3,6-carbazole). Efficiency values as high as 33.9 cd A(-1) are obtained, indicating that the linear structure in the absence of an encapsulation effect can also lead to a device performance that is comparable with that of either dendrimer or hyperbranched polymers.