Biocidally active cationic analogs of N-halamine having two biocidally active groups covalently bonded together in a single molecule and having general Formula (I). Compounds of Formula (I), and precursurs thereof, can be in solution form immobilized onto a substrate via physical coating or covalent chemical bonding to functionalize surfaces or added into materials as additives so as to render them biocidal. The biocidal solutions and substrates comprising the compounds or precursors of the present invention can then be used to inactivate pathogenic microorganisms. N-halamine-L-QUAT (I) wherein: the N-halamine may be a cyclic or acyclic N-halamine; L is C1-C6 alkyl, cyclic aromatic or non-aromatic ring, ether, ketone or any other organic linking structures, and QUAT has general formula ( II):
