In the title salt solvate (systematic name: 8-amino-5-ethyl-6-phenylphenanthridin-5-ium benzoate methanol monosolvate), C21H20N3+·C6H5CO2−·CH3OH, two ethidium cations, C21H20N3+, dimerize about a twofold axis through π–π interactions [inter-centroid separation = 3.6137 (4) Å]. The benzoate anions are connected through hydrogen bonding with the –NH2 groups of the ethidium cations and the –OH group of the MeOH molecule. The MeOH molecule also accepts a hydrogen bond from the –NH2 group of the ethidium cation. The result is a one-dimensional hydrogen-bonded chain along the b-axis direction.
