A series of phosphonate ester supported lanthanide complexes bearing functionalities for subsequent immobilisation on semiconductor surfaces are prepared. Six phosphonate ester ligands (L1-L6) with varying aromatic residues are synthesised. Subsequent complexation with lanthanide chloride or -nitrate precursors (Ln = La, Nd, Dy, Er) affords the corresponding mono- or dimeric lanthanide model complexes [LnX3(L1-L3 or L5-L6)3]n (X = NO3, Cl; n = 1 (Nd, Dy, Er), 2 (La, Nd)) or [LnCl2Br(L4-Br)2(L4-Cl)]n (n = 1 (Nd, Dy, Er), 2 (La, Nd)) (1-32). All compounds are thoroughly characterised, and their luminescence properties are investigated in the visible and NIR spectral regions, where applicable.