Abstract In contemporary years, hybrid lead halide perovskites nanocrystals (HPNCs) have emerged as core materials for low-cost solution-processable photovoltaic, light-emitting devices as well as in other optoelectronic fields, such as high-efficiency perovskite fluorescent quantum dots (quantum dot, QD). Although the high efficiency makes them an attractive active material, reducing the Pb-toxicity and enhancing the stability while sustaining the efficiency of the HPNCs devices is important for their successful commercialization in future. Here, we report for the first time the fabrication of excellent quality Pb-less, MAPb_1-x Sn _x Br₃ (x = 0 to 0.50) perovskite NCs by one-pot ultrasonication method. Interestingly, an outstanding photoluminescence quantum yield (PLQY) of 94% and better lifetime performance than 100% Pb-based HPNCs is obtained for Pb-less HPNCs. The successful incorporation of Sn MAPb_1-x Sn _x Br₃ HPNCs is confirmed by energy-dispersive x-ray (EDX) and x-ray photoelectron spectroscopy (XPS) analysis. Although the particle size for Pb-less HPNCs was different, the change in morphology and structure was minimal as confirmed by transmission electron microscopy (TEM) analysis. The optical analysis indicated bandgap tuning, which is evident by the blue shift of the band edge in absorbance spectra and photoluminescence peak after incorporating Sn²⁺. To the best of our knowledge, this is the highest achieved PLQY for Sn-substituted hybrid Pb-based HPNCs. The synthesis by using one pot ultrasonication method might be helpful for large-scale HPNCs production and can pave the way for future research on less-toxic and stable alternatives to Pb-based HPNCs.