HPS6 and lung cancer: In the dark, the Ru(II) complexes are inactive towards A549 human lung cancer cells, while notably complex C3, bearing a 4-piperidinyl- substituent and exhibiting a strong absorption band at 418 nm, possesses a good photocytotoxicity against irradiation with blue light (IC50 = 10.55 ± 0.30 μM), demonstrating that the conjugated NIs play a key role as an antenna in the photoactivation of these complexes.