Many of the new reactive dyes are bifunctional with identical or different reactive groupings in the dye molecule. Bifunctional dyes carry two reactive groups. Bifunctional dyes with good dyeing properties are created by the careful selection of the right reactive groups and right chromophores. It can easily be assessed that dyes with two identical reactive groups and dyes with two different reactive groups exhibit a higher fixation yield than-dyes with one group. 
The dyes were conventional Dichlorotriazine type, with the end condensation of B-sulphate ethyl sulphone to have different type of reactive group in a single molecule. 
Advantages of bifunctional dyes 
1. They offer enhanced reproducibility especially for medium to pale shades. 
2. They have high fixation rate. Excellent dyeing efficiency. 
3. Due to triazine ring system, they offer level dyeing performance for even non critical substrates. 
4. They have high fastness profile especially the washing characteristics. 
5. They have a brighter range of colors as compared to VS dyes. 
Key to  Abbreviations
ND = Non Dischargeable
D = Dischargeable
G = Good
M = Medium
F = Fair
P = Poor
S = Suitable
NS = Non Suitable
L = Less Suitable