Lipophilicity of the 1, 2-dithiole-3-thione nucleus was studied by stepwise calculation of log P values of some dithiolethiones from fragmental lipophilic constants of suitable fragments composing the nucleus, and the results were compared with experimental values. Fragmental constants necessary for these calculations were determined from log P values of suitable molecules. The influence of conjugation between the different parts was investigated.Fragmental lipophilic constants of unusual thio-fragments were assessed.