2-hydroxy-4-methoxybenzophenoneoxime (HMBO) was developed as a new analytical reagent for the gravimetric determination of Cu(II). In pH 2.5-9.0 the reagent gives brown coloured precipitate with Cu(II). Spectrophotometric methods revealed that the stoichiometry of the complex is 1:2 (metal : ligand). Beer’s law is obeyed up to 31.75 ppm of Cu(II). Molar absorptivity and Sandell’s sensitivity at 400 nm were found to be 7.0×102 Lmol-1cm-1 and 0.090 µg/cm2 respectively. The stability constant of Cu(II)-HMBO complex is found to be 6.13 x 109. Gibb’s free energy change for complex formation reaction was found to be -13.93 Kcal/mol. The reagent can be used for the analysis of brass.