Biguanide and dihydrotriazine derivatives, preferably substituted asymmetrical imidodicarbonimidic diamides derived from hydroxylamines, and compositions containing biguanide and dihydrotriazine derivatives are disclosed. In addition, methods of using the biguanide and dihydrotriazine derivatives, inter alia, as antimicrobial agents and methods of using the dihydrotriazine derivatives in biological assays are disclosed. Methods of making the biguanide and dihydrotriazine derivatives are also disclosed.