Grapheneoxide (GO) has been found to be highly efficient and recyclable carbocatalyst for the benign construction of heterocyclic molecule 1,4-benzothiazine from 2-aminothiophenol and 1,3-dicarbonyl compound. A vast range of highly functionalized 1,4-benzothiazine derivatives has been synthesized constituting a general and sustainable protocol. It is proposed that the large surface area of GO nanosheet