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A novel photochromic diarylethene bifunctional chemosensor with a hydroxybenzylidene-2-naphthohydrazide group was synthesized with multicontrollable and photoswitchable properties, induced by UV–vis light, acid/base, and metal ions in acetonitrile. The deprotonated derivative of the compound showed good photochromism and notable fluorescence enhancement. It could serve as a “naked-eye” colorimetric sensor for Ni2+. Moreover, its fluorescence was enhanced by 75-fold, turning from dark to bright jade green, upon the addition of Al3+. The compound formed complexes with Ni2+ and Al3+ in a 1:1 stoichiometry and could detect these metal ions at concentrations as low as 1.67 × 10–5 and 9.45 × 10–8 mol L–1, respectively. Additionally, it can penetrate into HeLa cells and can be used for the detection of intracellular Al3+.

A novel dual-response fluorescent sensor based on a diarylethene photoswitching unit and a dansylhydrazine functional group has been synthesized. The compound exhibited high selectivity for Fe 3+ and Cu 2+ with independent fluorescence signal outputs. In the presence of Fe 3+ , the sensor formed a 1:1 metal complex, resulting in a remarkable “turn-off” fluorescence signal. On the other hand, its fluorescence intensity was notably enhanced (turn-on) and a color change from bright yellow to bright blue was observed when the sensor interacted with Cu 2+ , which was due to the hydrolysis reaction of the dansyl acid dye, as confirmed by high-resolution mass spectrometry–electrospray ionization and infrared spectrum. The detection limits were 9.73 × 10 –8 mol L –1 for Fe 3+ and 3.49 × 10 –7 mol L –1 for Cu 2+ , respectively. From the unimolecular platform, two molecular logic circuits were constructed using the fluorescence emission intensity at 557/494 nm (Fe 3+ /Cu 2+ ) as the outputs and the combined stimuli of Fe 3+ /ethylenediaminetetraacetic acid, Cu 2+ , and UV/vis as the inputs. In addition, the sensor was successfully used to determine Fe 3+ in water samples from Ganjiang River and soil samples from Nanchang fields.