Ionic liquids are considered to be ‘green’ solvents on account of their non-volatility and non-flammability – which are results of their negligible vapour pressures – as well as reusability. On the basis of ecological concerns, ionic liquids seem to be an attractive alternative to conventional volatile organic solvents. In the present work, the reaction conditions for the synthesis of 1-butyl-3-methylimidazolium chloride were optimized on a small scale (~2 mL, 10 mmol) using a single-mode microwave system. The conditions obtained were subsequently transferred to various microwave reactors, both batch and continuous flow, as well as mono-mode and multi-mode, for the direct scale-up of the synthesis from 0.01 to 1.15 mol.