Excitation‐Dependent Luminescent Properties with Wide Range of Color Changes Using a Liquescent Cationic Gold(I) Complex

The solid form of a bis(trifluoromethanesulfonyl)imide ion salt of a cationic gold(I) complex ligated with cyclohexylisocyanide and an N ‐heterocyclic carbene is found to exhibit excitation‐dependent luminescent properties. The solid form, prepared by maintaining the liquid phase of the complex at 90 °C for 7 days followed by cooling to 25 °C, displays bluish‐purple, purple, orange, and red emissions under excitations at 340, 360, 370, and 380 nm, respectively. Excitation‐dependent emission spectra reveal that the observed color changes result from varying intensity ratios of two emission bands centered at 430 and 652 nm. Control experiments suggest that these excitation‐dependent luminescent properties originate from the coexistence of gold(I)–π aggregates and gold(I)–gold(I)‐interacted oligomers, which exhibit higher and lower bandgap energies, respectively.