The syntheses of new pyridazinethiocarboxamides are described using the reaction of Lawesson's reagent with pyridazine carboxamides or by reacting lithiopyridazines with phenylisothiocyanate. Metalation of 3-N-tert-butylpyridazinethiocarboxamides and carboxamides with LTMP followed by reaction of the lithio derivatives with various electrophiles gave access to a wide range of polysubstituted pyridazines