In the report, we described the ruthenium(II)-catalyzed C–H activation/cyclization of 2-arylquinazolinones with vinyl carbonate for the synthesis of different fused quinazolinones. Through this strategy, the 6-hydroxy-5,6-dihydro-8 H -isoquinolino[1,2- b ]quinazolin-8-one and 8 H -isoquino[1,2- b ] quinazolin-8-one have been obtained, respectively, under different temperatures. Additionally, the reaction features broad substrate scope and good yields, only producing carbon dioxide as byproduct. Moreover, we performed preliminary mechanistic studies of this reaction and proposed a possible mechanism. [ABSTRACT FROM AUTHOR]