Triplets of 2,2`-, 2,4`- and 4,4`- bipyridines (Bpy) are produced by laser flash photolysis in cyclohexane and by pulse radiolysis in benzene solution. The spectra and decay kinetics are compared. It appears that hydrogen abstraction from cyclohexane is more prominent for 4,4`-Bpy triplet as compared to 2,2`-Bpy and 2,4`-Bpy triplets. (author). 5 refs., 1 tab.