Phenalenone derivatives were efficiently constructed from 1,8-diiodonaphthalene and tertiary propynols via a one-pot domino reaction which eventually included Pd-catalyzed Sonogoshira coupling, Pd-catalyzed allylic oxidation and Pd-catalyzed Csp2–H activation. Moreover, the synthesized phenalenone derivative presented a practical application as a fluorescent chemosensor for fluoride anion with high sensitivity and selectivity.