The photochemistry of 3-methyl-2-(1-naphthyl)-2 H-azirine (1a) was investigated by the direct observation of reactive intermediates in matrixes at 10 K and by the characterization of reaction products in solutions. As already reported, the photolysis of the azirine 1a with the short-wavelength light (> 300 nm) caused the CC bond cleavage of the 2 H-azirine ring to produce the nitrile ylide 2. However, the products derived from the CN bond cleavage ...