3,6-Dihydr-oxy-2'-[(2-hydr-oxy-1-naphth-yl)methyl-eneamino]xanthene-9-spiro-1'-isoindolin-3'-one acetonitrile solvate.

The title compound, C(31)H(20)N(2)O(5)·C(2)H(3)N, was synthesized by the reaction of fluorescein hydrazide and excess 2-hydr-oxy-1-naphthaldehyde in acetonitrile. The spirolactam ring is planar and is nearly at right angles to the two benzene rings of the xanthene system. The dihedral angle between the two benzene rings of the xanthene system is 9.92†(4)°. In the crystal structure, the mol-ecules are linked into extended two-dimensional networks by inter-molecular hydrogen bonding. Acetonitrile mol-ecules are located in the voids between the two-dimensional networks.