The photochemical reactions of 5 H ‐benzo[ a ]phenothiazin‐5‐one with alkylthiols and thiophenol

6‐Alkylthio‐ and 6‐phenylthio‐5 H ‐benzo[ a ]phenothiazin‐5‐ones were prepared by the photochemical reaction of 5 H ‐benzo[ a ]phenothiazin‐5‐one with alkylthiols and thiophenol. The structures of newly prepared compounds were determined by elemental analysis, spectroscopic methods (ir, nmr and ms) and comparison with a sample prepared by an alternate route.