My questions is can 4 year dropper get admission in iisc through neet ug 2019 with good rank

see how many years you dropped is not the problem but the major problem is why you have not been doing well in NEET or how you can improve yourself
if you have taken admission into institutions like Aakash or Allen they provide you with quality study material and also mock examinations to improve your time management and question selection skills
If you are doing self study I would recommend you to follow books of Arihant and SL Arora in physics, op Agarwal and op tandon in chemistry and the Dinesh as well as two men series of biology which might help you along with your NCERT guidelines
make your own notes giving special attention to mechanics, thermodynamics, modern physics in physics, carbonyl compounds, atomic structure and molar concept as well as ionic chemistry in chemistry as well as the chapters on Microbiology, biotechnology, animal physiology, Human Physiology, genetics in biology