Nafion-H (R) served as an effective and environmental friendly heterogeneous catalyst for the convenient synthesis of a series of [1,2,4]triazolo[5,1-b]quinazolinones and [1,2,4]triazolo[1,5-a]pyrimidines by condensation of 3-amino-1,2,4-triazole as an amine source, different aldehydes and 1,3-dicarbonyl compounds in polyethylene glycol as solvent. The catalyst exhibited excellent recyclability without any significant loss of catalytic activity. This protocol offers several merits like simple work-up, mild conditions, higher yields and recyclability of the catalyst as well as solvent. Moreover, there was no need of product purification via column chromatography as the crude products obtained were very much pure. (c) 2013 Elsevier B.V. All rights reserved.