Mesoporous Aluminosilicate (AIKIT-5) has been found to be an efficient catalyst for one-pot synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives from dimedone, urazole, and aromatic aldehydes using acetonitrile as a solvent. This new method is simple, effective, ecofriendly, and consistently has the advantage of excellent yields (80-96%) and short reaction time (30-60 min). The effect of the catalyst weight, aluminum content in the catalyst, and the solvents on the synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives has been investigated. It has been found that the catalyst can be recycled for several times without much affecting its activity for a variety of organic transformations. (C) 2010 Elsevier Ltd. All rights reserved.