In this study, a miniaturized analytical methodology was introduced by combining vortex-assisted supramolecular-based dispersive liquid-liquid microextraction (VA-SUPRAS-DLLME) with flame atomic absorption spectrometry (FAAS) for determining nickel in plant samples. The SUPRAS (as extraction solvent) was prepared with a mixture of tetra-n-butylammonium hydroxide (Bu4NOH) and 1-undecanol. With both experimental study and computational chemistry approaches, it was shown that the effective extraction of Ni (II) ion was achieved by using Crystal violet as complexing reagent. Factors affecting the extraction efficiency of Ni(II) ion were optimized in detail. Under the optimal microextraction conditions, an enrichment factor of 195 was obtained. In addition, the linearity, the detection limit, and limit of quantification, and matrix effect were 3.3-600 ng mL(-1), 1.0 ng mL(-1), 3.3 ng mL(-1) and 7.8%, respectively. The validation of the method was checked by the analysis of certified reference material, addition-recovery tests, uncertainty measurement, and robustness. Following validation studies, the VA-SUPRAS-DLLME method is successfully applied to the determination of nickel in plant samples with quantitative recoveries.