Three indolylfulgenates possessing diesters of 14-crown-4 (2), 17-crown-5 (3), and 20-crown-6 (4) groups were synthesized and their photochromic behaviors in the presence or absence of alkali metal cations (Li+, Na+, K+) were investigated. Notable features are: (1) The association constant of Na+was the largest for3, and that for K+was the largest for4, (2) The association of E- and Z-forms are stronger than C-form. (3) In the cases of Na+-3and K+-4, no photocoloration occurred. (4) As for the photochromism of2, no effects of alkali metal species were observed. These phenomena were elucidated by molecular mechanics calculations.