A one-pot, one-step protocol combining hydrogen transfer initiated dehydration (HTID) of 1,3-propanediol (1,3-PDO), catalysed by [Cp*IrCl2(NHC)] (Cp* = pentamethylcyclopentadienyl; NHC = carbene ligand) complexes (1-5H and 1-3F), and self-aldol condensation (SAC) of propanal (2), allowed selective production of aldehyde 2-methyl-pent-2-enal (3), in ionic liquids with high substrate conversion. The Ir(III) pre-catalysts, and the ionic liquids, were recyclable. 3 could also be selectively produced in the presence of water, and in neat 1,3-PDO. The efficient, selective delivery of a value-added chemical from 1,3-PDO, a major product of many whole cell bacterial fermentation processes, shows that the combination of chemo-catalytic processing of the chemical platform via Cp*IrCl2(NHC) - catalysed HTID / SAC with bio-catalysis has the potential to allow direct valorisation of the bio-renewable feedstocks, such as waste glycerol and sugars, into valuable chemicals.