Psoralen compounds of Formula (I): wherein (N+ Aryl) is a member selected from the group consisting of nitrogen containing aromatic heterocycles of formulae (i)-(iii): wherein Z is a group of formula: wherein R is C1-C30 hydrocarbyl, which may be linear, branched or cyclic and contains from 1 to 15 carbon-carbon double bonds, which may be conjugated or unconjugated with one another or may include an aryl ring, and may contain one or more substituents; R1 is hydrogen, aryl, heteroaryl, alkyl, cycloalkyl, heterocyclyl, alkenyl, alkynyl, alkene-aryl, alkene-heteroaryl, alkene-heterocyclyl, alkene-cycloalkyl, fused cycloalkylaryl, fused cycloalkylheteroaryl, fused heterocyclylaryl, fused heterocyclyheteroaryl, alkylene-fused cycloalkylaryl, alkylene-fused cycloalkylheteroaryl, alkylene-fused heterocyclylaryl, alkylene-fused heterocyclyheteroaryl; n is an integer from 1 to 8 and X is a pharmaceutically acceptable counter ion; and their use in methods for the treatment of a cell proliferation disorder in a subject, pharmaceutical compositions containing the psoralen derivatives, a kit for performing the method, and a method for causing an autovaccine effect in a subject using the method.