Pyridine-protected CdSe nanopartictes decorated SWNTs spontaneously, producing a large loading of CdSe nanoparticles on the SWNTs. The absorption spectrum of this hybrid material reflects those of the components. CdSe nanopartictes of different diameters, core-shell nanopartictes, and nanorods were shown to decorate SWNTs this way, showing the versatility of this technique.