Employment of H₃L² (=2-(β-naphthalideneamino)-2-hydroxyethyl-1-propanol) in manganese–lanthanide cluster chemistry has led to the isolation of two new isostructural tetrametallic [Mn^III₂Mn^IVLn^III] complexes (Ln = Gd, Dy), with the Dy analogue displaying temperature and frequency dependent out-of-phase signals, thus indicating possible single molecule magnetism behaviour.