Method of quenching singlet and triplet excited states of photodegradable pigments, such as porphyrin compounds, particularly protoporphyrin IX, with conjugated fused tricyclic compounds having electron withdrawing groups, to reduce generation of singlet oxygen

A cosmetic or dermatological composition for coating a skin surface to protect the skin from getting damaging amounts of photogenerated reactive oxygen species when skin cell-contained or blood-contained pigments are exposed to sunlight, or other visible light comprising a cosmetically acceptable carrier, and a compound of Formula IIo:

• and mixtures thereof,
• wherein:
• A is selected from the group consisting of O, S, C═O, C═S,
• B1 and B2, are each independently selected from the group consisting of F,
• Cl, Br, I, CF3, CCl3, NR33+, NO2, CN, C(═O)R4, C(═O)OR1, SO2R5, aryl, and —C═CHR6,
• n is 0 or 1;
• each R1 is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl;
• R2 is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl;
• each R3 is independently selected from the group consisting of H and C1-C6 alkyl;
• each R4 is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl;
• each R5 is independently selected from the group consisting of H, O, OH, NH2, and Cl;
• and,
• each R6 is independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl,
• wherein if B1═CN, and B2═C(═O)OR1, then R1≠alkyl or cycloalkyl,
• wherein if n=0, B1═CN, then B2≠CN, and
• wherein if n=0, B1═C(═O)OR1, and B2═C(═O)OR, then R1≠alkyl or cycloalkyl.