The predicted n required to obtain the ZT max of SnS and SnSe are comparable to the carrier concentrations achieved in experiments, and these studies suggest the larger n required to optimise the ZT of the p-type Ge chalcogenides may also be achievable. Studies on n-doped SnS for PV applications have demonstrated n ≈ 10 18 in halogen-doped single crystals and n ≈ 5×10 18 cm -3 in Sn 1-x Pb x S thin films, while the recent study in Ref. achieved n ≈ 10 19 cm -3 in Sn 0.95 Se with 1% HfCl 4 . We therefore tentatively suggest that the lower n required for to achieve the predicted ZT max in the n-doped chalcogenides may be achievable with further optimisation. Of all the system considered, Pnma SnSe has the highest predicted average ZT max of 2.07 and 2.39 with p-and n-type doping, respectively, while n-type GeSe is predicted to attain a ZT max of 2.12 comparable to p-type SnSe. This would potentially make n-type GeSe a good match for p-type SnSe in a thermoelectric couple. Although the ZT max of the two R3m phases are not competitive with the Pnma systems, they are predicted to attain an industrially-viable mid-to-high temperature ZT > 1, which may make them useful for some applications. It is also worth noting that the highly-anisotropic electrical and thermal transport in the Pnma phases means a larger ZT max could be obtained if the growth direction could be controlled. For p-doped GeS, the largest ZT = 1.18 is along the layered b direction, where the κ latt is minimised, whereas in p-doped GeSe the largest ZT = 1.68 is obtained along the a direction which balances a smaller κ latt with more favourable electrical properties. For n-type doping, the largest PF and smallest σ are both obtained along the layered b direction, producing large ZT of 1.85 and 3.03.