A one-pot green and highly efficient method for the synthesis of propargylamines and diastereoselective synthesis of fused triazoles via three-component coupling in the presence of manganese(II) chloride as a catalyst and a catalyst-free 1,3-dipolar cycloaddition reaction, respectively, without using a co-catalyst or activator is reported. This methodology is efficient, eco-friendly, operationally simple and effective for reactions involving aromatic, aliphatic, and heterocyclic aldehydes, and provides an easy access to propargylamines in excellent yields, fused triazoles in good yield and excellent diastereoselectivities.