To date, ternary quantum-dot cellular automata (QCA) has been especially investigated and also is being advanced. Nonetheless, it should be possible to make interactions between binary QCA and ternary QCA circuits in order to have a versatile platform of designing. On the other hand, one of the most important concerns in QCA is minimising wire crossings because of low robustness caused by their manufacturing process and operational defects. In this study, a novel ternary-tobinary (and vice versa) converter is introduced firstly and a novel coplanar wire crossing scheme is proposed and presented afterwards. The latter scheme uses both kinds of binary and ternary QCA cells and provides a reliable crossover. Detailed circuit designs and results are presented to show correct functionality of the proposed circuits.