Temperature-dependent luminescence measurements provide significant fundamental insights by enabling the optical probing of the fine structure of the electronic ground state of Dy(III) ( 6 H15/2), which directly influences the magnetic performance of a single-molecule magnet (SMM). Furthermore, the temperature sensitivity of the spectral features imparts potential applications in thermal sensing. We have performed variable temperature solid-state photoluminescence of the complexes 1-3 in the temperature range of 300 K -15 K (1, 3) and 300 K -13 K (2) along with the free ligands (bik, bik* and acac) at 300 K. On excitation at 320 nm, the emission bands due to the f-f transitions are visible for complex 3 at 300 K, which shows sharp intense peaks at 484 nm and 580 nm corresponding to 4 F9/2 → 6 H15/2 and 4 F9/2 → 6 H13/2 respectively. Upon lowering the temperature to 15 K, the intensity of both the peaks increases with the appearance of very low intense hump at 545 nm ( 4 I15/2 → 6 H13/2) When the spectrum of complex 3 at 300 K was compared to the free ligands (i.e. acac and bik-Et) spectra under similar conditions (Figure ), we observed ligand-centric emissions at 434 nm and 463 nm coming from acac and 468 nm coming from bik-Et ligand is completely quenched in complex 3. This indicates that when complex 3 is excited at the intra-ligand charge transfer band at 320 nm, the coordinated ligands i.e. acac and bik-Et on the absorption of the energy, transfer the electrons from the ground state to an excited singlet state (S0 → Sn) or an excited triplet state (S0 → Tn). From there, the energy transfer takes place to the excited states of Dy(III), namely, 4 I15/2 and 4 F9/2, which act as the emitter states. For complex 1, on excitation at 320 nm, at 300 K, the PL measurement reveals a bik-Et ligand-based emission at 465 nm with several humps between evolution of peaks at 442 nm ( I15/2 → 6 H15/2), 484 nm ( 4 F9/2 → 6 H15/2), 544 nm ( 4 I15/2 → 6 H13/2) and 577 nm ( 4 F9/2 → 6 H13/2) 37, 48, 56 (Figure ). These peaks are distinct from those obtained from the free ligands dbm (432 nm, 466 nm) and bik-Et (468 nm) at 300 K (Figure ). However, the emission contribution from the ligand is not completely quenched, as evident from the broad nature of the spectra. The PL spectrum of complex 2, obtained at 300 K on excitation at 320 nm, shows a bik-Me ligand-based emission at 468 nm and shoulders at 484 nm ( 4 F9/2 → 6 H15/2) and 545 nm ( 4 I15/2 → 6 H13/2). Upon lowering the temperature to 13 K, the PL spectrum shows sharp peaks at 484 nm ( 4 F9/2 → 6 H15/2), 545 nm ( 4 I15/2 → 6 H13/2) and 578 nm ( 4 F9/2 → 6 H13/2), along with the appearance of humps at 422 nm (emission contribution coming from dbm ligand) and 440 nm ( 4 I15/2 → 6 H15/2). Similar to complex 1, the ligand-based emissions are not completely quenched in complex 2 (Figures S15). Additional variable temperature PL measurements were performed by applying an excitation wavelength of 420 nm for complexes 1 -3 (see SI for further details) (Figure and).