The pH indicator proposed is a water-soluble dye based on benzo[de]antracen-7-one. Dissolving in buffered aqueous solution, it changes color from yellow to orange and in the mean time decreases its fluorescence emission as a function of the amine concentration. Viscose fabric, dyed with the same dye has been investigated as a new reversible colorimetric and fluorescent sensor material for ammonia and aliphatic amines in buffered solution. The high value of the dye pK(a) and the influence of the textile matrix on the selective detection of dimethylamine compared to ammonia, trimethylamine, and metylamine have been studied. The different response of the solution and textile matrix as well as the optical analyses both as a color change and a fluorescence emission have been discussed. The advantage of this sensor is the fact that depending on the analytical problem to be solved and the available instrumentation it can be used either as a fluorogenic or as a chromogenic chemosensor. In addition, the textile sensor is characterized by facile fabrication, low cost, sensibility, and reproducibility. (c) 2007 Wiley Periodicals, Inc.