The phase transition of the chalcogen substituted CuBrTe, CuBrTexSe1-x, system was investigated by X-ray diffraction, specific heat and electrical conductivity measurements in the temperature range between 10 and 473 K. Te atoms can be substituted by Sr atoms in the range 0.75 less than or equal to x less than or equal to 1 as a solid solution. The replacement of Te with Se atoms in CuBrTexSe1-x leads to an increase in conductivity, especially in the beta- and gamma -phases.