Enlightened by the above prior arts, an alternative approach is presented in this paper; a catonic dye intercalated bentonite with organophilic surface treatment was used as a latent fingerprint development agent. An advantage with bentonite is its high cation exchange capability (CEC) which results in high levels of dye incorporation into the clay particles. Moreover its surface can be further modified by silylation via relatively simple treatment procedures, which have been reviewed by other researchers (Bergaya and Lagaly, 2001; Herrera, 2004). The process can be applied to the production of a variety of colored and fluorescent dye clay particles. In the present research, R6G and MB were chosen as examples of guest molecules for demonstration of the effect, since R6G is a highly fluorescent cationic dye with important applications and both dyes are thus far extensively investigated in the research of dye–clay complexes