The oxidation of α- and β-naphthol/PhOH/ sensitized by protoporphirin has been studied in benzene and Ccl4 at 25 °C by a laser flash photolysis apparatus with a time resolution of 10 ns. Kinetics of the1O2 decay in the presence and in the absence of PhOH was followed spectrophotometrically by using 1,3-diphenylizobenzofurane /DPBF/ as an acceptor for1O2. The effective rate coefficients/keff/of the consumption of DPBF were measured as a function of the concentration of PhOH. In CCl4 the value of keff remained practically unchanged after the addition of PhOH at a concentration of 10−5–10−4M, at the same time short-lived intermediates were formed which absorb at 400 nm in such solutions. In benzene at [PhOH]<4×10−2M\(k_{1_{0_2 + \alpha - naphthol} }^{overall} \) ≾ 5×105M−1s−1 and\(k_{1_{0_2 + \beta - naphthol} }^{overall} \) ≾ 1×105M−1s−1, as it has been calculated. Long-lived intermediates have not been observed in C6H6.