Thallophilic interactions and Tl-aryl π-interactions are competitive with cation-cation repulsion: [LTl2L]2+ dications as salts of weakly co-ordinating anions.

The synthesis and characterization by single-crystal X-ray diffraction of two thallium salts of the non-co-ordinating anion [B{3,5-(CF3)2C6H3}4] are reported. They possess Tl-Tl contacts supported by Tl-aryl interaction. This cation association overcomes both electrostatic repulsion and cation-anion size and charge matching considerations in the [LTl2L](2+) dications so formed.