In 2012 we demonstrated that molecular spacer layers could be intercalated in between FeSe layers resulting in a dramatic enhancement of the critical temperature: FeSe is itself an 8K superconductor, but the incorporation of LiNH2/NH3 raises the transition temperature to 43K. This proposal aims at studying new molecular intercalated iron selenides that can now be prepared following this discovery. We will be using muon-spin rotation to focus on measurements of the penetration depth, detection of any magnetic order, and studying light-ion diffusion.