A facile synthetic approach towards the synthesis of 2-substituted carbamoyl (or thiocarbamoyl)-3-aryl-3,3a,4,5-tetrahydro-2 H-benz[g]indazoles 3a-r and their 2-acylating derivatives 4-6 was reported via the reaction of 2-unsubstituted-2 H-benz[g]indazoles 2 with isocyanates or their thio analogues, acid anhydrides and aliphatic or aromatic carboxylic acids. The molluscicidal activity of the products was screened.