Generally, a 3d transition metal center with 3d 4 -3d 7 electronic configuration in a (distorted) octahedral geometry shows such bistability in a detectable way, where depending on the ligand field strength () and spin pairing energy (P), electrons will occupy different t2g and eg orbitals (Fig. ). A comparable magnitude of  and P, i.e., ||  |P| brings the opportunity to switch the spin-state between LS and HS upon applying the external stimuli, which is termed as SCO. SCO is associated with significant changes in structure, e.g., metal-ligand bond distances, unit cell parameters, electronic, optical, and magnetic properties . Consequently, a large number of physical methods and techniques, e.g., single-crystal, powder X-ray diffraction analyses, magnetic measurements using modern SQUID magnetometer and PPMS susceptometer, heatcapacity measurements, spectroscopic studies (UV-Vis-NIR, IR, Raman, NMR, Mössbauer, fluorescence, etc.), have been employed to fully characterize the SCO systems. Temperatureinduced SCO has been represented as the most studied one, where entropy-driven HS state and enthalpy-driven LS state are favored at high and low temperatures respectively following the thermodynamic relationship G = H -TS. Depending on the presence of various long-and short-range interactions, called cooperativity in SCO material, significantly influences thermoinduced SCO, the nature of SCO has been noticed to be gradual, abrupt, with hysteresis, stepwise, and incomplete as shown in Fig. . Despite the major improvements in SCO systems over the last few decades, iron(II)-based SCO materials have been most extensively studied among other 3d metals where spin-state switching occurs between the LS (t 6 2g e 0 g, S = 0, 1 A1) and the HS (t 4 2g e 2 g, S = 2, 5 T2) states. Several excellent works exist on SCO systems in various dimensions (0D -3D), nanomaterials, hybrids, etc. . Apart from thermo-induced SCO, spin-state switching between LS state to HS meta stable photo-induced state under light irradiation at low temperature identified as light-induced excited spin state trapping (LIESST) effect has been well studied particularly in iron(II) and iron(III) systems. The photo-induced HS state relaxes back to the LS ground state at a particular temperature known as TLIESST after heating the sample in the dark . Many excellent works on the LIESST effect have been reported to which we refer the reader . Incorporation of one or more physical properties, such as optical, dielectric, and luminescence, with the SCO allows the production of stimuli-responsive multifunctional materials where external perturbation can tune and control both the SCO and associated physical properties in a synergic way . Towards multifunctional SCO materials, the simultaneous incorporation of SCO with dielectric and luminescence has been gaining great attention due to their potential application towards the realization of magneto-optical switches or a new regeneration of magneto-electrical devices . Reading the significant modification of the luminescence signal from luminescent-SCO material during the SCO phenomenon, one can easily signify the spin state switching process and LS/HS state population. Although such a synergic correlation between SCO and luminescence was first described two decades ago , it has recently received great attention in material research.