The development of nanomaterials with special optical window is critical for clinical applications and the optoelectronic industry. In this work, eight kinds of samarium-based metal organic compound nanoparticles (Sm–Fe, Sm–Ga, Sm–Mn, Sm–Na, Sm–Nb, Sm–W, Sm–Cu, and Sm–Al) were synthesized through a solution method. They show polychromatic-photoluminescence spectra extended from the UV to near-infrared (NIR) region when excited by 280 nm, 380 nm, 480 nm, 580 nm, and 785 nm light. They emit direct white light with respect to UV excitation. Tunable white-to-green fluorescence can be achieved by variation of excitation light around 300–400 nm. When they are excited by a 785 nm light source, they show intense fluorescence around 800–1100 nm, which is promising for NIR bio-imaging. Their application in multicolor ultra-wide-range bio-tissue fluorescence imaging is demonstrated by UV (359–371 nm), blue (450–490 nm), green (540–552 nm), and NIR light (central wavelength = 785 nm) excitation with pig kidney tissue samples.