In this paper, the dosimetric characteristicsof a colored metal complex solution were investigated. Nickel nitrate hexahydrate and 1,5-diphenylcarbazone were made as a liquid solution chemical dosimeter at three concen trations with an inexpensive and simple synthesis for use in gamma irradiationin the range of 20-1000 Gy. The maximum absorbance was observed spectrophotometrically at a maximum wavelength of 530 nm. The paper presents the dosimeter response, radiation chemical yield (G(x)), stability, and repeatability. The results showed that this solution is suitable for use in routine dosimetry in the 20-1000 Gy range