The present review describes our recent work on a variety of thioaminyl and related radicals. Thioaminyl radicais are generated by oxidation of the corresponding RNHSR<sup>`</sup> with lead dioxide or photolysis of RN(SR`)₂. It has been found that most thioaminyl radicals are quite persistent in solution, even in the presence of oxygen and can be isolated as radical crystals or N-N coupled dimers. The molecular structures of the isolated radicals have been determined by X-ray crystallographic analyses. The dimers, upon dissolution, dissociate into the corresponding radicals at room temperature, and the enthalpies and entropies of dissociation for the equilibria are determined. The ESR studies for thioaminyls show an extensive delocalization of the unpaired electron from the nitrogen radical center to R and SR`. Ab initio molecular orbital calculations on H-N-S-H predict a trans-planar form as the most stable conformation. This is in agreement with the X-ray crystallographic results from the isolated thioaminyl radicals. The cyclic voltammetric behavior of the isolated radicals is also described.