A universal approach for a development of a nonstoichiometry (NS) measurement technique for binary compounds has been proposed. The approach is based on a pi‐T‐x diagram analysis for binary chemical compounds with different mutual arrangements of stoichiometry line, congruent sublimation line and SLV area. NS detection limits for PbTe, CdS, CdSe, CdTe, ZnSe, ZnTe from 10−4 up to 5 × 10−6 mol.% with a relative accuracy <18 rel.% were found out for the different excess component.