A simple and sensitive supramolecular solvent-based dispersive liquid liquid microextraction method was described for the separation/preconcentration and spectrophotometric detection of rhodamine B. The microextraction method, which was realized at ambient temperature for the detection of rhodamine B, was carried out by using supramolecular solvents such as tetrahydrofuran and decanoic acid. The method was based on analyses of rhodamine B by using UV-Vis spectrophotometry at 558 nm. The influences of some parameters such as pH, sample volume, eluent solutions, centrifugation time, and ultrasonic bath time were optimized. The effects of various matrix ions were also investigated. Moreover, the limit of detection and limit of quantification were calculated as 0.49 mu g L-1 and 1.47 mu g L-1, respectively. The preconcentration factor was 30. The relative standard deviation was determined as 5.8% in 0.5 x 10(-4) M rhodamine B. The procedure was validated by addition/recovery tests. The microextraction method was applied to determination of rhodamine B in tap water samples and cosmetic samples such as nail polish, rouge, and lipstick.