Some new azo disperse dyses 2-(2-chlorobenzylidiene amino) -4-phenyl-5-(aryi azo)-thiazoles were synthesised. Their dyeing performance on polyester fibre and their antibacterial, antitubercular and antifungal activities were assessed. These derivatives were characerised by elementl analysis. IR and NMR spectra. The fastness properteis of these dyes were evaluated by appying them to polyester fibre. The antibacterial activities were evaluated by applying them to polyester fibre. The anitbacterial actvitives were evaluated E.cli, S. aureus, S. paratyphi B. vulgaris and Enterobactor. The antibervular activity was evaluated against H37Rv strain M. tuberculosis and antifungal activity was found C. alibcan