Abstract: The reaction of aromatic nitriles with perylenetetracarboximides affords colorants which fluoresce strongly in the long-wave region and are 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. R1 to R8 are each H, CN, halogen or optionally mono- or polysubstituted hydrocarbon groups. Establishing a suitable pH achieves a large Stokes shift in these colorants via the ESPT mechanism.