Anthraquinone-based chemosensor L with pyridine units as additional functional groups has been found to show pH-dependent multiple coordinationmodes towards differentmetal ions (Co²⁺, Ni²⁺ and Cu²⁺). Based on these different absorption changes, this differential colorimetric chemosensor L has found promising applications as a multiple-mode molecular logic system, i.e., OR, three - input NOR, three - input INHIBIT, TRANSFER and 1:2 DEMUX.

2-(2-methoxyphenyl)-4,5-diphenyl-1H-imidazole 1, an imidazole-based compound, was found to sense Cu²⁺ ions via fluorescence and absorption spectroscopy over a number of other metal ions. During Cu²⁺ sensing, the chemosensor 1 followed a “switch-off” mechanism. Job’s plot supported 1:1 stoichiometry of 1-Cu²⁺ complex. The 1-Cu²⁺ complex formed in situ underwent different absorption changes with OH⁻ ions. These differential absorption changes observed with the addition of Cu²⁺ and OH⁻ ions were used to mimic AND logic gate using A_274nm as output.