how to achieve bidirectional data transfer between nrf52 and android phone?

[Pranay]

Hi, Basically i want my nRF52 DK should be able to transmit data to connected android device and also be able to receive data from android,data is kind of logs.

[run_ar]

I would suggest that you take a look at the ble_app_uart example in our SDK. You can test this with one of our development apps. e.g. nRF Connect or nRF toolbox for Android. Example code for Android can be found here.