Ethidium tetra-phenyl-borate aceto-nitrile disolvate.

In the title solvated salt, (C 21 H 20 N 3 ){B(C 6 H 5 ) 4 }·2CH 3 CN (systematic name 3,8-di-amino-5-ethyl-6-phenyl-phenanthridin-5-ium tetra-phenyl-borate aceto-nitrile disolvate), the dihedral angle between the tricyclic fused ring system (r.m.s. deviation = 0.021 Å) and the pendant phenyl group of the ethidium cation is 84.91 (7)°. The {B(C 6 H 5 ) 4 } - anion has a typical tetra-hedral structure. The aceto-nitrile solvent mol-ecules do not accept hydrogen bonds from the -NH 2 groups of the ethidium ions.