As suspected, it is not possible to simply transfer the learnings from chromium(III) photophysics to its heavy cousin molybdenum(III). Instead our results suggest the following guidelines for the future design of photoactive molybdenum(III) complexes: 1) Unlike with chromium(III), dedicated strong-field ligands are not required to avoid deactivation via back-intersystem crossing. Even in the heteroleptic complexes MoX3(ddpd) with the weak, -donating chlorido and bromido ligands, the ligand field splitting was sufficiently large. 2) Ligands should be selected for a weak nephelauxetic effect, forming more ionic Mo-L bonds, to push the emissive spin-flip states to higher energies. 3) High-energy oscillators (C-H, N-H, O-H) in close proximity to the metal center should be avoided to reduce multi-phonon relaxation, either by ligand design or by ligand deuteration. 4) Rigid ligands, preferably in meridional configuration can help to limit deactivation of the excited states via trigonal distortion. 5) Shielding of the metal center from nucleophilic attacks can increase the overall stability against oxidation and hydrolysis.