In addition to the papers (1965–2005) referenced in the main article [] pyrrolyl squaraines were listed in a 1974 US patent from IBM as one of the examples of a squaraine dye that can be used in electrophotographic plates [], a 1979 US patent from Eastman Kodak in relation to electrophoretic migration imaging processes [], a 1982 US patent for use in electrophotographic reproduction [], two concurrent 1988 US patents from Eastman Kodak for use as negative working photoresists [] and imaging dyes [], a 2004 US patent from Asahi Denka for their use as optical filters and optical recording materials [], and a 2005 US patent from BASF for use in optical data storage applications [].
References from 2006 onwards listing pyrrolyl squaraines have included a 2007 US patent from KyoWa Hakko Chemical covering their use as optical filters for electronic display devices [], a computational study in 2007 on the diradical nature of both squaraine and croconaine dyes [], a 2008 US patent from Adeka Corporation for use as optical filters and optical recording materials [], a 2008 US patent from Fuji Xerox for use as a colorant [], a 2009 US patent from Kyowa Hakko Chemical for use as optical filters [], a 2009 review (in Spanish) of oxocarbons and pseudooxocarbons [], a 2010 US patent from Fuji Xerox for use as a colorant [], and a 2013 US patent from Adeka Corporation for use in a color conversion filter [].
Conflicts of Interest
The author declares no conflicts of interest.
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