Synthesis, structures, electrochemistry and magnetic properties of a cyano-bridged {Fe2Co2} molecular square

► One cyano-bridged {Fe2Co2} molecular square has been synthesized via rational design. ► Strong ferromagnetic interactions exist between the FeIII and CoII ions. ► The compound exhibited quasi-reversible waves in the reduction process. ► The compound exhibited irreversible waves in the oxidation process.