Abstract The preparation of some 6-and/or 7-substituted derivatives of 1, 2, 3- benzothiadiazole is described. The reactivity of some compounds was investigated in view of the possibility that 1, 2, 3-benzothiadiazoles may behave as masked diazo compounds. 7- Diazo or diazonium compounds were prepared but no interaction with the thiadiazole part could be observed.