Iridium complex 1 is a lab-on-a-molecule for recognising and quantifying cysteine/homocysteine and tryptophan in a mixture of all proteinogenic amino acids. UV-Vis and photoluminescence channels are suitable for quantification of homocysteine and cysteine in aqueous media, e.g. by emission enhancement at 606 nm, while tryptophan was selectively quantified in the electrochemiluminescence channel.