Abstract: Preparation of alkylthio and/or arylthio-substituted diketo-diaryl-pyrrolopyrroles (DPPs) of the formula Ia and dithio-bridged bis-diketo-diaryl-pyrrolopyrroles (bis-DPPs) of the formula Ib in which in formula Ia G is phenyl substituted by at least one arylthio or alkylthio group, and G1 is G or a carbocyclic or heterocyclic radical, by reacting a haloaryl with a thiol or thiolate, and in formula Ib G5 is a phenylene, G6 is G1 but not G, and G7 is alkylene, cycloalkylene or phenylene, by reacting two haloaryls with a dithiol or dithiolate, which comprises reacting a thiol or thiolate with a halo-diketo-diaryl-pyrrolopyrrole (“halo-DPP”) of the formula IIa in which G2 is a halogenated phenyl group and G3 is G2 or G1, or reacting a dithiol or dithiolate with two halo-diketo-diaryl-pyrrolopyrroles (“halo-DPPs”) of the formula IIb in which Hal is halogen such as fluorine, chlorine, bromine or iodine, and G6 is G1, and also novel DPPs a

Abstract: A process for the preparation of compounds of formula I ##STR1## by reacting a pyrrolopyrrole of formula ##STR2## wherein X.sub.1 is a group selected from ##STR3## X.sub.2 is a group selected from ##STR4## or has the same meaning as X.sub.1, with a secondary amine of formula ##STR5## in the molar ratio 1:2, in the presence of an anhydrous dipolar aprotic solvent and of an amount 0.1 to 15 times in excess of stoichiometric proportion, based on the amine of formula III, of an anhydrous organic base, in the temperature range from 50.degree. to 230.degree. C. and under a pressure from 0 to 10 bar.The substituents R.sub.1 to R.sub.8, Y and Hal are as defined in claim 1.The compounds of formula I are especially suitable for use as photoconductive substances.

Abstract: Process for the manufacture of 2-(2-hydroxyphenyl)benztriazoles of the formula I ##STR1## wherein R.sub.1 denotes hydrogen or halogen, R.sub.2 denotes hydrogen, alkyl, alkoxy, alkylsulphonyl, acylamino, --SO.sub.3 H, --COOH or halogen, R.sub.3 denotes hydrogen, alkyl, cycloalkyl, aralkyl, aryl or halogen, R.sub.4 denotes hydrogen, alkyl, alkoxy or --OH and R.sub.5 denotes hydrogen, alkyl, cycloalkyl, aralkyl, aryl, carboxyalkyl, alkoxy, acylamino or halogen, characterized in that a 2-(2-hydroxyphenyl)-benztriazole-1 oxide in the formula III ##STR2## is reacted with 0.5 to 0.6 mol equivalent of hydrazine hydrate at a temperature above 100.degree. C, in a high-boiling ether as the solvent and in the presence of a base.

Abstract: Substituted 2-nitro-2'-hydroxy-azobenzenes are manufactured by coupling a phenol dispersed with a dispersing agent in water with a solution, in an inorganic acid, of a diazotized o-nitroaniline at a pH value not exceeding 2.The azobenzenes obtained are intermediate products for benztriazoles.