The set of four ternary coordination compounds of terbium were prepared with diketone 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione (TFDH) and four different neutral ligands (L) having formula Tb(TFDH)3L. Resulting compounds were characterized using different techniques including NUV absorption studies, photoluminescence (PL) spectroscopy, electrochemical and thermal analyses. PL spectra confirmed the green luminescence of synthesized complexes by exhibiting characteristic dominant 5D4 → 7F5 peak around 545 nm. Electronic and optical energy gap values lying at ∼3.5 eV reveals their potential to use in semiconductor materials. All the spectral results are in good agreement with each other and highlight their utility in lighting, biomedical imaging and sensors etc. Display omitted •Ternary Tb(III) complexes were prepared using β-diketone and 1,10-phenanthroline based neutral ligands.•NMR spectra exhibited dipolar shift due to the paramagnetic nature of terbium ion.•The optical band gap and the electronic band gap lie within the semiconductor range.•5D4.→ 7F5 MD transition is responsible for the green luminescence in the synthesized complexes.