<p>A green, metal-free protocol for the synthesis of pharmaceutically relevant 1,2,4-triazolidine-3-thiones is described using 6&#xa0;mol% biodegradable and recyclable choline chloride as a catalyst. The reaction between aryl/heteroaryl aldehydes or ketones and thiosemicarbazide proceeds efficiently in a green H₂O/EtOH solvent system at room temperature. This method offers significant advantages, including short reaction times (10–20&#xa0;min), excellent yields (90–97%), high atom economy (&gt; 89%), and broad substrate tolerance for aldehydes, ketones, and heterocycles. The catalyst is easily recovered and reused for four cycles without significant loss of activity. Environmental metrics underscore the sustainability of the process, with a low E-factor (&lt; 5), a favourable Eco-Scale score of 97, and simplified, chromatography-free purification. This approach aligns with green chemistry principles, providing a scalable and environmentally benign route to a valuable class of bioactive heterocycles.</p> Graphical abstract <p></p>