Radicalanions were generated by reduction of aliphatic diazenes with sodium–potassium alloy combined with u.v. irradiation (primary alkyl azo compounds), sodium–potassium alloy (secondary and tertiary alkyl azo compounds) and with crotylpotassium combined with u.v. irradiation (primary, secondary, and tertiaryl alkyl azo compounds); nitrogen hyperfine coupling constants range from 0.775 to 0.883 mT