Comparative data on the cyanovinyl and carboethoxyvinyl groups, and on the nature of the N‐substituents in a range of styryl dyes are reported, with particular respect to substituent effects on colour, dyeing properties and fastness to light and sublimation. Substitution patterns especially advantageous (and otherwise) in these dyes are concluded together with new data presented in respect of the colour of N‐β‐cyanoethyl derivatives in different solvents.

The synthesis of a series of dyes derived from reaction of 2‐methyl‐4‐(N‐ethyl‐N‐hydroxyethyl)amino, lidicyano‐styrene with acid chlorides, chloroformates, isocyanates and isothiocyanates is described. Data relevant to dye characterization by electron‐impact induced fragmentation is reported. Dyeing and fastness properties of the dyes on cellulose secondary acetate, cellulose triacetate, nylon 6.6 and polyester fibres are discussed in terms of dye structure. Comparison is made between some related dyes derived from 2‐methyl‐4‐(N‐ethyl‐N‐β‐aminoethyljamino‐β,βdicyanostyrene.

The synthesis of a series of disperse dyes based on 4‐amino‐β,β‐dicyanostyrene and ethyl‐α‐cyano‐4‐aminocinnamate is described; various preparative routes to these dyes are discussed. Infra‐red and mass spectra characteristics of the dyes are reported, indicating data relevant to the characterization and identification of these commercially useful dye classes.

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During an investigation into structure‐property relationships of a series of ethyl‐α‐cyano‐4‐aminocinnamate disperse dyes, the 4‐(N‐β‐cyanoethyl‐N‐β‐acetoxyethyl) amino derivative showed anomalous behaviour on attempts to purify it. This compound was shown to be susceptible to dimerization to a colourless cyclobutane derivative, the structure of which was established by nmr spectroscopy. The dimerization is interpreted in terms of ‘Topochemical’ factors. Typical nmr spectra characteristics of some monomeric styryl disperse dyes are also indicated.