An attempt has been made in in-situ preparation and application of two isomers (para and meta) of aminophenyl-b-sulphatoethyl sulphone reagents (PABSES and MABSES) with three dichlorotriazinyl dyes i.e. CI Reactive Orange 86, CI Reactive Red 11 and CI Reactive Blue 168 to generate mixed hetero bifunctional dyes in dye bath. Dyeing results when compared with similar targeted type of commercially available Sumifix Supra dyes were found not up to the mark. Build up properties of all in situ prepared dyes were lower except for few light depth of shades as compared to preformed commercial Sumifix Supra dyes. This could be because of inefficient condensation of dichlorotriazinyl dyes with the aminophenylb-sulphatoethyl sulphone. However, meta isomer of aminophenyl-b-sulphatoethyl sulphone appeared to be more effective than the para isomer.