The present invention relates to novel 2,5-bis{[alkyl (or aryl) imino]aminophenyl}furans and thiophenes of the general formula ##STR00001## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of H, alkyl, alkoxy, halide, and alkylhalide groups; R.sub.5 is H, alkyl or aryl; R.sub.6 is H, alkyl, aryl, or NR.sub.7R.sub.8, in which R.sub.7 and R.sub.8 are each independently selected from the group consisting of H, alkyl and aryl; and X is O, S or NR.sub.9, in which R.sub.9 is H or alkyl, and to the use of such compounds.