The n,π complexes of s-trinitrobenzene (TNB) and the tetraalkylammonium halides have been studied from the analytical point of view in nonaqueous solvents. Mixtures of tetraalkylammonium chlorides and TNB give little evidence of charge transfer spectra in the visible region, but both the corresponding bromides and iodides form colored complexes with TNB. Proton donors are poor solvents, but acetonitrile, methylene chloride, and chloroform are useful for analytical work. Using excess TNB, plots of absorbance at 410, 415 or 425 mü versus concentration of the bromides are linear and can be used for analysis.