Heterocyclic derivatives of naphthalene‐1,8‐dicarboxylic anhydride. Part II. Colour and dyeing properties on synthetic fibres of some substituted 7H‐benzimidazo[2,1‐a]benz[de]isoquinolin‐7‐ones

The effect on colour resulting from substitution in the phenyl and naphthyl rings of 7 H ‐benzimidazo [2,1‐ a ]benz[ de ]isoquinolin‐7‐one (I) is discussed; dycing and fastness properties of these dyes on synthetic fibres are described and the synthesis of some new 1,8‐naphthalimides and derivatives of I recorded.