An analytical microextraction procedure was developed and applied for Cu(II) microextraction from natural waters, red pepper, black pepper, thyme, hashish, hair, and tobacco samples. The microextraction process was based on the chelation of Cu(II) from aqueous solutions with 4-(2-thiazolylazo) resorcinol, which is then moved to the organic supramolecular phase by ultrasonic waves. The organic phase, consisting of tetrahydrofuran and 1-decanol, was isolated by centrifugation. The extracted and preconcentrated copper was determined by microsampling flame atomic absorption spectrometry. The microextraction conditions and the operating parameters were optimized using the pH of 6, 200 mu L of 0.1% of 4-(2-thiazoly-lazo) resorcinol, and ultrasonic enhancement for 5 to 8 minutes. The ultrasound-assisted supramolecular solvent liquid phase microextraction procedure resulted in a limit of detection (LOD) of 1.13 mu g L-1 and was applied for Cu(II) determination in samples with different matrices.