Two benzothiazospironaphtopyran photochromic compounds have been synthesized by reacting 2-hydroxy naphthaldehyde with 2-methylenebenzothiazole derivatives respectively, under microwave irradiation in good yields:61% for SP1 and 59% for SP2. Triethylamine was used as catalyst and anhydrous ethanol as solvent. The elemental analysis, IR, MS, 1H NMR were used to identify the title compounds. Their spectral properties were studied. The λ max values of their corresponding ring-opening compounds were linearly correlated with the polarity of solvents.
