Reactions of N,P‐Ligands as Ph2P(o‐NMe2C6H4) (1L), 2,6‐iPr2C6H3NHC(Ph)=NC6H4(o‐PPh2) (2L), and Ph2PN(R)PPh2 (R=iPr (3L), cyclo‐C6H11 (4L), tBu (5L), CH2C4H7O (6L)) each with dicobalt octacarbonyl produced complexes [1LCo(CO)3]2 (1), [2LCo(CO)(μ‐CO)2Co(CO)3] (2), [3LCo(CO)3]+[Co(CO)4]− (3), [3LCo(CO)2]2 (4), [4LCo(CO)2]2 (5), [5LCo(CO)2]+[Co(CO)4]− (6), and [6LCo(CO)2]+[Co(CO)4]− (7). Complexes 1–7 have all been structurally characterized by X‐ray crystallography, IR and NMR spectroscopies, and elemental analysis. Catalytic tests on transformation of ethylene oxide (EO), CO and MeOH into methyl 3‐hydroxypropionate (3‐HMP) indicate that complexes 1–7 are active, where ion‐pair complexes 3 and 6–7 behave more excellently (by achieving 88.4–93.6% 3‐HMP yields) than the neutral species 1–2 and 4–5 (35.0–46.5% 3‐HMP yields) when the reactions are all operated at 2 MPa CO pressure and 50 °C in MeOH solvent. Density functional theory (DFT) study by selecting 3 as a model suggests a cooperative catalytic reaction mechanism by [Co(CO)4]− and its counter cation [3LCo(CO)3]+. The cobalt‐homonuclear ion‐pair catalyzed hydroalkoxycarbonylation of EO is present herein.