3-{1-[2-(2-Chloro-phen-yl)hydrazinyl-idene]-2,2,2-trifluoro-eth-yl}-7-diethyl-amino-2H-chromen-2-one.

The title compound, C(21)H(19)ClF(3)N(3)O(2), has a structure related to other coumarin derivatives that have been used as fluorescent probes of metal ions. The dihedral angle between the coumarin ring system and the chlorobenzene ring is 42.99†(9)°. Intra-molecular hydrogen bonding occurs via N-H⋯O and N-H⋯Cl inter-actions, generating S(7) and S(5) rings, respectively. The crystal packing is stabilized by weak C-H⋯O hydrogen bonds.