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The properties of a bichromophore photochromic spirooxazine with a hydroxynaphthyl ideneimine fragment in position 8 were studied in solutions in the presence of alkali and alkaline earth metal salts. The changes in the absorption spectra of the initial form of this compound upon complexation are due to the electron density redistribution in the conjugation chain due to the incorporation of the metal cation into the ionophoric center of the chelating molecule. A complexation scheme was proposed and the stability constants of the resulting complexes were estimated. The complexation of the photoinduced merocyanine form of the compound increases its lifetime. This process is due to the interaction of the metal ion with both the chelating ionophoric center and the oxygen atom of the mercocyanine form. The efficiency of complexation of both the initial and the merocyanine forms depends on the electrostatic properties of the metal cations.The transformation of photochromic compounds con taining various ionophoric functional groups into metal ion complexes is a method for influencing their spectral and photochemical properties. These compounds could find application as selective chromo and fluoroiono phores for determination of various metal cations. 1-6 Cur rently, the properties of crown containing spiropyrans, spirooxazines, and chromenes are under extensive re search. However, the scope of practical use of crowned compounds is restricted by their high cost. Therefore, it is pertinent to search for photochromic compounds con taining complexones of a different nature.Here we present the results of a study of the behavior of bichromophore spirooxazine (BCSO) in solutions in the presence of alkali and alkaline earth metal salts. BCSO ExperimentalThe synthesis of BCSO was described in our previous publi cation. 7 The spectrophotometric measurements were carried out in solutions in acetonitrile (Aldrich, water content 0.005%). The complexes were prepared using Mg, Ba, and Pb perchlorates (chemically pure grade). The metal salt to ligand concentration ratio (C M /C L ) was varied from 0.1 to 100 at C L = 2•10 -4 mol L -1 . The electronic absorption spectra of the solutions were mea sured on a Cary 50 spectrophotometer in cells with an optical path of 0.2 cm at 25 °C. The photostationary absorption spectra were recorded on a USB2000 fiber optics spectrometer (Ocean Optics) with continuous irradiation of the solutions using a DRSh 250 gas discharge mercury lamp (λ = 365 nm). The ki netic measurements were carried out using a laboratory setup that ensured recording the kinetics of photoprocesses over time spans of down to 1 ms.