An electrophotographic photoconductor includes an electroconductive support and a photoconductive layer formed thereon containing a diamine compound represented by formula (I): ##STR1## wherein R.sup.1, R.sup.2, and R.sup.3 each is independently a substituted or unsubstituted alkyl group or aryl group; R.sup.4 is hydrogen, an alkyl group or an alkoxyl group; n is an integer of 1 to 3; and ##STR2## is a substituted or unsubstituted bivalent arylene group or a bivalent heterocyclic group. This diamine compound is useful as a photoconductive material for electrophotographic photoconductors.