[(2-{[3′,6′-Bis(ethyl­amino)-2′,7′-dimethyl-3-oxospiro­[1H-isoindole-1,9′-9H-xanthen]-2-yl}eth­yl)amino­meth­yl]phenol

The title compound, C(35)H(38)N(4)O(3), was prepared as a spiro­lactam ring formation of rhodamine dye for comparison with a ring-opened form. The xanthene ring system is approximately planar. The dihedral angles formed by the spiro­lactam and phenol rings with the xanthene ring system are 85.7 and 109.4°, respectively. Each of the mol­ecules in the crystal structure contains one intra­molecular O—H⋯N hydrogen bond, and they form inter­molecular N—H⋯O hydrogen-bonded chains along the [100] direction. Weak inter­molecular C—H⋯O hydrogen-bonding contacts connect the infinite chains via crystallographic inversion centres to form a two-dimensional network.