Aerated benzene solutions containing anthracene together with one of the carotenoids, β-carotene, β-apo-8′-carotenal, ethyl β-apo-8′-carotenate and canthaxanthin were subjected to laser photolysis. Under these conditions oxygen quenching of triplet anthracene produces the excited singlet state of molecular oxygen O2* (1δg) which in turn transfers energy to the carotenoid thereby yielding its triplet state, the absorption of which was monitored thereby confirming electronic energy transfer as the mechanism of quenching of O2*(1δg) by these carotenoids and enabling the bimolecular quenching constansts which vary from 1.2 – 1.45 × 10101 mol−1s−1to be measured.