A compound of Formula or a pharmaceutically acceptable salt thereof: wherein: A and B are independently selected from absent, H or a moiety of Formula, with the proviso that at least one of A and B is a moiety of Formula; wherein: R and R 1 are each independently selected from H, alkenyl, alkynyl, alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl and heteroaryl substituents; or R and R 1 taken together with the atom to which they are attached form a 3- to 7-membered ring, wherein said 3- to 7-membered ring optionally contains up to two heteroatom groups selected from O, N R 4, S, SO and SO 2, and is optionally substituted with 1 to 4 alkoxy, F or Cl substituents; Y, independently for each occurrence, is selected from R 2, OR 2, NH 2, NHR 2, and NR 2 R 3; R 2 is selected from alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are each optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl or heteroaryl substituents; R 3 is selected from alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are each optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl or heteroaryl; or R 2 and R 3 may be taken together with the nitrogen atom to which they are attached to form a 3- to 7-membered ring, wherein said 3- to 7-membered ring optionally contains up to three heteroatom groups selected from O, NR 4, S, SO and SO 2, and is optionally substituted with alkoxy, F or Cl; R 4 is, independently for each occurrence, selected from H or C 1 -C 8 alkyl; and X and X 1 are each independently an anion or absent, provided that X is absent only when A is absent, and X 1 is absent only when B is absent; and provided that neither A nor B is R and R 1 are each independently selected from H, alkenyl, alkynyl, alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl and heteroaryl substituents; or R and R 1 taken together with the atom to which they are attached form a 3- to 7-membered ring, wherein said 3- to 7-membered ring optionally contains up to two heteroatom groups selected from O, N R 4, S, SO and SO 2, and is optionally substituted with 1 to 4 alkoxy, F or Cl substituents; Y, independently for each occurrence, is selected from R 2, OR 2, NH 2, NHR 2, and NR 2 R 3; R 2 is selected from alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are each optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl or heteroaryl substituents; R 3 is selected from alkoxy, aryl, heteroaryl, C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl, wherein in each of the C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl optionally up to three carbon atoms are replaced by a heteroatom group independently selected from O, NR 4, S, SO and SO 2, thereby making a heteroalkyl or heterocyclyl substituent, and wherein said C 1 -C 8 alkyl and C 3 -C 7 cycloalkyl are each optionally substituted with from 1 to 4 C 1 -C 8 alkyl, alkoxy, aryl or heteroaryl; or R 2 and R 3 may be taken together with the nitrogen atom to which they are attached to form a 3- to 7-membered ring, wherein said 3- to 7-membered ring optionally contains up to three heteroatom groups selected from O, NR 4, S, SO and SO 2, and is optionally substituted with alkoxy, F or Cl; R 4 is, independently for each occurrence, selected from H or C 1 -C 8 alkyl; and X and X 1 are each independently an anion or absent, provided that X is absent only when A is absent, and X 1 is absent only when B is absent; and provided that neither A nor B is