Seven ferrocenyl-based unsymmetrical azines 3a–3f and 5a were synthesized under metal-free conditions in good yields.

The compounds 3f and 5a have shown to be excellent multichannel recognition receptors for Hg²⁺ and Cu²⁺.

1,1′-disubstituted ferrocene-based azines 3f has higher sensitivity than 1-disubstituted ferrocene-based azines 5a.

Different substituent groups on the phenyl have significant influence on the sensitivity.

The color of the solution containing chemosensor 3f changed from yellow to colorless, upon the addition of Hg²⁺ and Cu²⁺ ions.