The study was conducted to investigate the effect of potassium schoenite and ethrel on yield, quality, biochemical changes, and physiological loss in the weight of grapevines. Crimson Seedless vines grafted on dog ridge rootstocks at ICAR – NRC for grapes, Pune under the tropical condition of India was selected for this study. The grapevines were planted by adapting a 3.3m × 1.6 m and trained on the Y system. Pre-harvest spray of potassium scheonite (2.50 g/L and 5.00 g/L) and ethrel (300 and 600 ppm) along with control untreated vines was carried out at the veraison stage. The grapes bunches were harvested after attaining harvestable maturity with TSS of 17.50° Brix. The highest bunch weight (287.16 g), berry weight (3.70 g), and yield per vine (11.25 kg/vine) were recorded in treatment with potassium schoenite 5.00 g/L. In terms of quality parameters viz., TSS (18.43 ° Brix), total acidity (0.604 %) were recorded with the pre-harvest spray potassium schoenite at 5.00 g/L. Among the different treatments, ethrel at 600 ppm enhances total anthocyanins, total tannins, and total berry flavonoids. It was increased in the shelf life of Crimson Seedless by decreases in physiological weight in loss (10.96 %), Fallen berries (1.36 %), and Rotten berries (0.68 %) on 7th day of observation in this investigation.