A novel, green, solvent-free, and efficient method has been developed for the one-pot reductive amination of carbonyl compounds using thiamin hydrochloride as a catalyst. This method has performed reductive amination on various functionalized amines and aldehydes, including aliphatic, aromatic, and heteroaromatic ones. The reductive amination of the carbonyl compounds occurred in a single step without any side reaction. The key benefits of this technique included its easiness, greener protocol, quick transformation, variety of substrates, outstanding yield, metal-free, and catalyst recyclability. This helps to make the procedure practical, affordable, and biodegradable.