Polymethine Dyes

Abstract

This article defines the specific molecular and electronic characteristics that qualify a colorant as a polymethine dye. It also delineates various subclasses of polymethine dye before going on to describe the spectroscopic characteristics associated with the polymethine chromogen, which has led to this class of colorant becoming so important to numerous sectors of industry and academia. The influences of molecular structure on spectroscopic properties that are peculiar to polymethine dyes form the subject of brief discussion before moving on to a survey of the chief commercial applications for this type of colorant. A short summary of nascent technologies for which polymethine dyes constitute key materials then follows, along with signposting of information sources on their synthesis.