A compound of Formula or a salt thereof: wherein: each of R 1 and R 2, independently, is hydrogen, alkyl, cylcoalkyl, heterocyclic, heterocycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, alkyl-hetero-alkyl, alkynyl, alkylene, alkylene-hetero-alkylene, alkenylene, alkylene-hetero-alkenylene, alkynylene, or alkylene-hetero-alkynylene; or, R 1 and R 2, together with the carbon atom to which they are attached, form a 3- to 7-membered saturated or unsaturated cyclic or heterocyclic ring containing 1 to 3 heteroatoms each independently being O, S, or NH; each of A and B, independently, is alkylene, alkylene-hetero-alkylene, alkenylene, alkenylene-hetero-alkenylene, alkylene-hetero-alkenylene, alkynylene, cycloalkylene, alkylene-cycloalkylene, alkylene-cycloalkylene-alkylene, alkenylene-cycloalkylene, alkenylene-cycloalkylene-alkenylene, alkylene-cycloalkylene-alkenylene, alkynylene-cycloalkylene, alkynylene-cycloalkylene-alkynylene, heterocycloalkylene, alkylene-heterocycloalkylene, alkylene-heterocycloalkylene-alkylene, alkenylene-heterocycloalkylene, alkenylene-heterocycloalkylene-alkenylene, alkylene-heterocycloalkylene-alkenylene, alkynylene-heterocycloalkylene, alkynylene-heterocycloalkylene-alkynylene, cycloalkenylene, alkylene-cycloalkenylene, alkylene-cycloalkenylene-alkylene, alkenylene-cycloalkenylene, alkenylene-cycloalkenylene-alkenylene, alkylene-cycloalkenylene-alkenylene, alkynylene-cycloalkenylene, alkynylene-cycloalkenylene-alkynylene, heterocycloalkenylene, alkylene-heterocycloalkenylene, alkylene-heterocycloalkenylene-alkylene, alkenylene-heterocycloalkenylene, alkenylene-heterocycloalkenylene-alkenylene, alkylene-heterocycloalkenylene-alkenylene, alkynylene-heterocycloalkenylene, alkynylene-heterocycloalkenylene-alkynylene, arylene, alkylene-arylene, alkylene-arylene-alkylene, alkenylene-arylene, alkenylene-arylene-alkenylene, alkylene-arylene-alkenylene, alkynylene-arylene, alkynylene-arylene-alkynylene, heteroarylene, alkylene-heteroarylene, alkylene-heteroarylene-alkylene, alkenylene-heteroarylene, alkenylene-heteroarylene-alkenylene, alkylene-heteroarylene-alkenylene, alkynylene-heteroarylene, or alkynylene-heteroarylene-alkynylene; each of R 3 and R 4, independently, is hydrogen, alkyl, cycloalkyl, heterocyclic, heterocycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, alkoxyalkyl, or alkynyl; and both of m and n are 1. each of R 1 and R 2, independently, is hydrogen, alkyl, cylcoalkyl, heterocyclic, heterocycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, alkyl-hetero-alkyl, alkynyl, alkylene, alkylene-hetero-alkylene, alkenylene, alkylene-hetero-alkenylene, alkynylene, or alkylene-hetero-alkynylene; or, R 1 and R 2, together with the carbon atom to which they are attached, form a 3- to 7-membered saturated or unsaturated cyclic or heterocyclic ring containing 1 to 3 heteroatoms each independently being O, S, or NH; each of A and B, independently, is alkylene, alkylene-hetero-alkylene, alkenylene, alkenylene-hetero-alkenylene, alkylene-hetero-alkenylene, alkynylene, cycloalkylene, alkylene-cycloalkylene, alkylene-cycloalkylene-alkylene, alkenylene-cycloalkylene, alkenylene-cycloalkylene-alkenylene, alkylene-cycloalkylene-alkenylene, alkynylene-cycloalkylene, alkynylene-cycloalkylene-alkynylene, heterocycloalkylene, alkylene-heterocycloalkylene, alkylene-heterocycloalkylene-alkylene, alkenylene-heterocycloalkylene, alkenylene-heterocycloalkylene-alkenylene, alkylene-heterocycloalkylene-alkenylene, alkynylene-heterocycloalkylene, alkynylene-heterocycloalkylene-alkynylene, cycloalkenylene, alkylene-cycloalkenylene, alkylene-cycloalkenylene-alkylene, alkenylene-cycloalkenylene, alkenylene-cycloalkenylene-alkenylene, alkylene-cycloalkenylene-alkenylene, alkynylene-cycloalkenylene, alkynylene-cycloalkenylene-alkynylene, heterocycloalkenylene, alkylene-heterocycloalkenylene, alkylene-heterocycloalkenylene-alkylene, alkenylene-heterocycloalkenylene, alkenylene-heterocycloalkenylene-alkenylene, alkylene-heterocycloalkenylene-alkenylene, alkynylene-heterocycloalkenylene, alkynylene-heterocycloalkenylene-alkynylene, arylene, alkylene-arylene, alkylene-arylene-alkylene, alkenylene-arylene, alkenylene-arylene-alkenylene, alkylene-arylene-alkenylene, alkynylene-arylene, alkynylene-arylene-alkynylene, heteroarylene, alkylene-heteroarylene, alkylene-heteroarylene-alkylene, alkenylene-heteroarylene, alkenylene-heteroarylene-alkenylene, alkylene-heteroarylene-alkenylene, alkynylene-heteroarylene, or alkynylene-heteroarylene-alkynylene; each of R 3 and R 4, independently, is hydrogen, alkyl, cycloalkyl, heterocyclic, heterocycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, alkoxyalkyl, or alkynyl; and both of m and n are 1.