The methodology of this study relies on the screening of three sets of CO pressure (5, 15 and 50 bar) and ten common organic solvents: toluene, anisole, acetonitrile (MeCN), dimethyl carbonate (DMC), 1,4-dioxane, dimethoxyethane (DME), ethyl acetate (EtOAc), acetone, tetrahydrofurane (THF), and N,N-dimethylformamide (DMF). There is an interplay between CO pressure and the nature of the solvent for the generation of a potential active species (Scheme 3). While this step depends of course on the coordination properties of the LB, balance should also be found in terms of CO pressure: CO may be released during the disproportionation, which is then favoured at lower pressure, but concurrently CO pressure is required for the carbonylation itself. a Conditions: PL (0.5 mol‧L -1 ) and mesitylene (internal standard, 10 mol%) with [Co2(CO)8] (5 mol%) in the solvent (2 mL), heated for 6 h under CO pressure. PL conversions and SA yields were measured by GC-MS analysis; the selectivity was calculated as the ratio between yield and conversion. Due to the uncertainty of the analysis method, conversions lower than the yields can be obtained, and in that case, the selectivity value was reported as >99%. Selectivity was not reported and noted "/" when the conversion was <1%.