Phenothiazine-picric acid (1/1)

The title compound, C12H9NS center dot C6H3N3O7, is a 1:1 adduct of neutral phenothiazine (pz) and picric acid (pa). A weak bifurcated N- H center dot center dot center dot(O,O) hydrogen bond links the pa and pz species and an intramolecular O-H center dot center dot center dot O bond occurs within the pa molecule. The O atoms of one of the pa nitro groups are disordered over two positions of almost equal [0.54 (2): 0.46 (2)] occupancy. The dihedral angle between the pz aromatic ring planes is 11.81 (10)degrees.