Abstract: Compounds which are useful as sensitizers of photoconductors, having the general formula: ##STR1## in which: like symbols represent identical substituents,at least 4 of R.sup.1 to R.sup.9 represent hydrogen atoms and the remaining R.sup.1 to R.sup.9 pairs of groups independently represent:(i) hydrogen, an alkyl group having from 1 to 18 carbon atoms, a substituted alkyl group, or an aryl or substituted aryl group,(ii) a halogen atom, a cyano group, a carboxy or alkoxycarbonyl group, a hydroxy group, an alkoxy group, a nitro group or a sulfonic acid group, providing that not more than two such groups (ii) are present in each ring,(iii) an acylamino group, a secondary acylamino group or a tertiary amino group in which the pendant substituent groups on the nitrogen atom are alkyl, aryl or aralkyl, providing not more than two such groups (iii) may be present in each benzocarbazole ring, and(iv) any two groups R.sup.1 to R.sup.