The spectrophotometric determination of the substance dibenzo [b,f]-1,4-oxazepine (CR) the form of an ionic associate with the anionactive dyes of the type of azo dyes, sulphonephthaleins and anthraquinones after extraction with chloroform was worked out. Conditional extraction constants K(ex)' were calculated and equilibrium ratios D and extraction yields E of ionic associates were determined. On the basis of detection limit L(Q), the dyes Alizarine Black S (0.7 mug/nil) and Orange II (0.8 mug/ml) were recommended for extractive spectrophotometric determination of the substance CR.