Squaraine dyes
 Novel squaraine dyes and compositions of matter containing such dyes are disclosed. The novel squaraine dyes have an absorption maximum greater than 600 nanometers and are particularly useful in conjunction with a helium/neon (He/Ne) laser. Some of the squaraine dyes are hydrophilic and are therefore water soluble or water compatible and others of the squaraine dyes are lipophilic. 
Syntex (U.S.A.) Inc.
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C07C C07C C09B C07F
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Thomas L. Donald Chiu C. John Chun-Hua
Tarnowski Berger Chang Pease Chuang