The present invention relates to novel 2,5-bis {[alkyl(or aryl)imino]aminophenyl}furans and thiophenes of the general formula in which R1, R2, R3 and R4 are each independently selected from the group consisting of H, alkyl, alkoxy, halide, and alkylhalide groups; R5 is H, alkyl or aryl; R6 is H, alkyl, aryl, or NR7R8, in which R7 and R8 are each independently selected from the group consisting of H, alkyl and aryl; and X is O, S or NR9, in which R9 is H or alkyl, and to the use of such compounds.