Sodium hexanitritocobaltate(III) is primarily used in analytical chemistry as a reagent for the detection and determination of potassium ions. It forms a distinctive yellow precipitate with potassium, which is useful for qualitative and quantitative analysis. Additionally, it is employed in the synthesis of other cobalt complexes due to its stable coordination structure. In some cases, it is also utilized in research involving nitrite chemistry and coordination compounds, providing insights into the behavior of transition metal complexes.