N,N′-Bis(2-pyridylmethyl)propylendiamine (1) and N,N′-bis(2-pyridylmethyl)-1,5-diamino-3-thiapentane (2) have been functionalised at the secondary nitrogen atoms with dansylamidoethyl (L 1 , L 3 ), 2-quinolinylmethyl (L 2 , L 4 ) and ferrocenylmethyl (L 6 , L 7 ) pendant arms with the intention to study their potentiality as receptor units in molecular sensors. The optical response of L 1 –L 4 to the presence of the metal ions Cu 2+ , Zn 2+ , Cd 2+ , Hg 2+ and Pb 2+ has been investigated in MeCN/H 2 O (4:1 v/v) solution. The electrochemical response of L 6 and L 7 to the presence of the same metal ions has been investigated in anhydrous MeCN/CH 2 Cl 2 10:1 (v/v) solution. Results are compared and discussed with the aim to clarify the mutual role played by the bis(2-methylpyridyl)alkyl(thioalkyl)diamines and the signalling units attached to them in reaching the selectivity of the responses observed.