Thermal and microwave-assisted [3+2] cycloadditions between differently substituted propiolamidinium tetraphenylborates 3a–d and N-methyl-C-phenylnitrone, benzyl azide, and N-(3-azidopropyl)phthalimide were studied. The activation parameters of the [3+2] cycloaddition between alkyne 3a and benzyl azide were determined. A Diels–Alder reaction between the terminal alkyne 3a and cyclopentadiene could