Aryl 2-bromobenzoates and aryl 2-bromocyclohex-1-enecarboxylates are cyclized by microwave irradiation in dimethylformamide in the presence of KCO to give the corresponding 6 H-benzo[ c]chromen-6-ones and their 7,8,9,10-tetrahydro analogues, respectively, in 50-72% yields. Aryl 3-bromoacrylates are also converted into 2 H-chromen-2-ones under the employed conditions.

A green construction of trinuclear N-fused hybrid scaffolds by transition metal-free double C(sp2)–N coupling of 2-(2-bromoaryl)- and 2-(2-bromovinyl)benzimidazoles with 2-aminoazoles under microwave irradiation has been developed.

2-(2-Bromovinyl)- and 2-(2-bromoaryl)-benzimidazoles, including their 4,7-dimethoxy analogs, react with primary amides by microwave irradiation (or usual heating) in dimethylformamide in the presence of a catalytic amount of CuI along with a base to give the corresponding benzo[4,5]imidazo[1,2- c ]-pyrimidines and -quinazolines in good yields. Treatment of benzo[4,5]imidazo[1,2- c ]-pyrimidines and -quinazolines having methoxy group on benzimidazole moiety with aqueous ceric ammonium nitrate affords unprecedented N-fused hybrid scaffolds, benzo[4,5]imidazo[1,2- c ]-pyrimidin-6,9-diones and -quinazoline-8,11-diones, respectively, in high yields.

2‐(2‐Bromoaryl)‐ and 2‐(2‐bromovinyl)‐benzimidazoles are coupled and cyclized with cyclic ureas as new building blocks in dimethylformamide in the presence of a catalytic amount of a copper catalyst and a base to give the corresponding trinuclear N‐fused hybrid scaffolds in good yields. Trinuclear N‐fused hybrid scaffolds having methoxy group on benzimidazole moiety are readily oxidized to unprecedented benzimidazolequinone‐fused hybrid scaffolds in high yields by treatment of ceric ammonium nitrate in acetonitrile/H2O.