The complexation of IrCl3 center dot 3H(2)O with the electron-deficient phosphines (L1-L6) respectively afforded a bifunctional catalyst possessing the dual functions of transition metal complex (Ir-III-P) and Ir-III-Lewis acid for tandem hydroformylation-acetalization of olefins. The best result was obtained over L5-based IrCl3 center dot 3H(2)O catalytic system which corresponded to 97% conversion of 1-hexene along with 92% selectivity to the target acetals free of any additive. The crystal structure of the novel Ir-III-complex of Ir-III-L4 indicated that the electron-deficient nature of the involved phosphine warranted Ir-center in +3 valence state without reduction, which served as the Lewis acid catalyst for the subsequent acetalization of the aldehydes as well. Moreover, as an ionic phosphine, L6-based IrCl3 center dot 3H(2)O system immobilized in RTIL of [Bmim]PF6 could be recycled for 6 runs without the obvious activity loss or metal leaching. (C) 2019 Elsevier Inc. All rights reserved.