The synthesis and the application of some disazo disperse dye derivatives of Nphenylnaphthylamine on polyester fibre and nylon fibre are described. These derivatives exhibited changes in both colour shades and fastness properties on the two fibre substrates. The fastness properties also revealed that the dyes have affinity for polyester and nylon fibres. The dyes were characterised by spectral methods: 1HNMR, 13CNMR, FTIR and UVVIS. The very high value of max of dye 5e showed that it can be a potential candidate for organic photoconductor.