Tert-alkylphenoxy-substituted polycyclic compounds of the general formula I where P is a conjugated polycyclic radical which is stable to bases and nucleophiles, optionally bears aryl substituents and contains no group from the group consisting of —CO—NH—CO—, —COOH and —CO—O—CO—; R is C1–C8-alkyl, whose carbon chain may be interrupted by one or more groups selected from the group consisting of —O—, —S—, —NR1—, —CO— and/or —SO2— and which may be monosubstituted or polysubstituted by C1–C6-alkoxy or by a 5- to 7-membered heterocyclic radical which is attached via a nitrogen atom and may contain further heteroatoms and be aromatic; C5–C8-cycloalkyl whose carbon chain may be interrupted by one or more groups selected from the group consisting of —O—, —S—, —NR1—, —CO— and/or —SO2— and which may be monosubstituted or polysubstituted by C1–C6-alkyl; R1 is hydrogen or C1–C6-alkyl; Hal is chlorine and/or bromine; m is from 0 to 15; n is from 1 to 16, subject to the proviso that the sum m+n is ≦16, are prepared and used.