In the crystals of the title N-halo­methyl­ated quaternary ammonium salts, there are short I⋯I− inter­actions of 3.564 (4), 3.506 (1) and 3.55781) Å for compounds (I), (II) and (III), respectively. In (I), mol­ecules are linked by C—H⋯I− and C—H⋯π inter­actions, together with the I⋯I− short contacts, forming ribbons along [100]. In (II), there are only C—H⋯I− inter­actions, which together with the I⋯I− short contacts, lead to the formation of helices along [010]. In (III), apart from the I⋯I− short contacts, there are no other significant inter­molecular inter­actions present.