1,2,4-Triazine derivatives with 2-amino-1,3,4-thiadiazole moieties at C5 position were synthesized by solvent-free nucleophilic ipso-substitution of the cyano group in 3,6-di(hetero)aryl-1,2,4-triazine-5-carbo-nitriles. 5-Amino-1,2,4-triazines were obtained as minor products of the reaction.