The ability of a poly(2,7-carbazole) to disperse three samples of commercially available single-walled carbon nanotubes (raw HiPCO, purified HiPCO, and CoMoCAT nanotubes) has been investigated. UV-vis-NIR absorption spectroscopy, photoluminescence mapping, Raman spectroscopy, and atomic force microscopy were used to characterize the dispersions obtained. It was found that the polycarbazole preferentially interacted with semiconducting nanotubes and was efficient at dispersing smaller diameter (under 1.1 nm) carbon nanotubes. Larger diameter nanotubes could be dispersed to form stable suspensions in THF; however, it appeared that there were some small bundles present. It was found that annealing the purified HiPCO nanotubes at high temperature under an inert atmosphere greatly enhanced the ability of the polycarbazole to disperse the nanotubes and remove metallic species. (C) 2014 Wiley Periodicals, Inc.