I have a grid with two columns of coro type. and the values for the dropdowns are being pulled from the database. I would like to have a functionality where in the second coro values should populate based on the selected value of the first coro. how can i do that?

There is no built in functionality for such use-case.
If you need some kind of workaround - please contact us directly at support@dhtmlx.com and provide your ref. number.