Descriptions of sample preparation for optical measurements and calculation of fluorescence QY. Figures showing effect of BME on SWNTs; the reversibility of brightening effect; fluorescence time trace of a bright (6,4) SWNT; histogram of SWNT lengths as collected by AFM; time-dependent change in fluorescence intensity of a SWNT ensemble upon addition of reductants; changes in absorption of SWNTs upon addition of DTT; effect of DTT upon an ensemble of SDS-coated SWNTs. Table of intensity changes for individual SWNTs, table comparing intensities of single CdTe/ZnS QDs to single DNA-wrapped SWNTs enhanced with DTT. This material is available free of charge via the Internet at http://pubs.acs.org.