Synthesis of 4-methyl tetrahydrobenzofurano-(6, 7-b)coumarin (I) and spectrophotometric determination of copper (II) with I has been described. The system obeys Beer's law in the concentration range of 1.6~6 ppm of copper (II) and molar absorptivity is 12,700 at 370 nm. Sensitivity was found to be 0.0036 μg cm^(-1) for 0.001 absorbance. The effect of various parameters have also been reported.