Fluorescent, heterocyclically fused perylenes

A compound of the formula

• in which one pair Q1 and Q2 or one pair Q2 and Q3, and optionally from 0 to 3 pairs Q3 and Q4, Q5 and Q6, Q6 and Q7 and/or Q7 and Q8, in each case in pairs, together form a heterocyclic ring
• the remaining Q1, Q4, Q5 and Q8 which do not form a heterocyclic ring are each hydrogen, and the remaining Q3, Q6 and Q7 which do not form a heterocyclic ring are each independently R5 or R6, preferably
• in which
• R1 to R8 are each independently H, F, Cl, Br, I or {linear C1-C37alkyl}(-R9)m, m is from 0 to 12,
• R9, and in the case of multiple R9 each R9 independently of all other R9, is H, F, Cl, Br, I, CN or {linear C1-C18alkyl}(-R10)n, n is from 0 to 6,
• R10, and in the case of multiple R10 each R10 independently of all other R10, is H, F, Cl, Br, I, CN or {linear C1-C18alkyl},
• where no or from 1 to 10 —CH2— units in each {linear C1-C37alkyl}, if appropriate independently of all other {linear C1-C37alkyl}, may be replaced by R11, and/or no or from 1 to 6 —CH2— units in {linear C1-C18alkyl}, and in the case of multiple {linear C1-C18alkyl} in each {linear C1-C18alkyl} independently of all other {linear C1-C18alkyl}, may be replaced by R12, and
• R11 and R12 are each independently, and in the case of multiple R11 and R12 each R11 or R12 independently of all other R11 and R12, is —CO—, —O—, —S—, —Se—, —Te—, cis or trans —CH═CH—, cis or trans —N═CH—, —C≡C—, 1,2-, 1,3- or 1,4-phenylene, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-pyridinediyl, 2,3-, 2,4-, 2,5- or 3,4-thiophenediyl, 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6- or 2,7-naphthylene, in which 0, 1 or 2 ═CH— may be replaced by ═N—, or 1,2-, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 1,9-, 1,10-, 2,3-, 2,6-, 2,7-, 2,9-, 2,10- or 9,10-disubstituted anthracylene in which 0, 1 or 2 ═CH— may be replaced by ═N—,
• or any two R9, R10, R11 and R12 substituents together form, in a single pair or multiple pairs, a direct bond, so as to form rings, preferably cyclohexane or benzene rings,
• where R4 may optionally be bonded by a direct bond to R4 of a second molecule, and/or R8 may be bonded by a direct bond to R8 of a second molecule, so as to form dimers, trimers, tetramers or higher oligomers.