2-[(2-Hy­droxy­benz­yl)amino]­pyrazinium perchlorate–2-[(pyrazin-2-yl­amino)­meth­yl]phenol (1/1)

In the crystal structure of the title co-crystal, C(11)H(12)N(3)O(+)·ClO(4) (−)·C(11)H(11)N(3)O, the perchlorate ion is disordered about a twofold rotation axis with the Cl atom located on the twofold rotation axis; the 2-[(2-hy­droxy­benz­yl)amino]­pyrazinium cation and the neutral 2-[(pyrazin-2-yl­amino)­meth­yl]phenol mol­ecule are disordered about the rotation axis in a 1:1 ratio. These two are connected by a pyrazine–pyrazine N(1)—H⋯N(4) hydrogen bond. The cation, whose two aromatic rings are twisted along the –CH(2)—NH– bond by 76.8 (1)°, is a hydrogen-bond donor to the perchlorate ion through the N atom of this link.