Cut the green bell pepper  lengthwise, finely chop the onion n tomatoes into small pieces, Wash thoroughly the chicken pieces with turmeric powder,heat oil in a kadai, add the mustard seeds, urad dal n cumin seeds to the hot oil n let them splutters.... now add the finely chopped onion n tomato pieces n cook them ..add the chicken breast pieces to the veggies n stir them occasionaly until they change their colour, now add the red chilli powder, garam masala powder , dhania powder(corianderpowder) n salt as per need to the chicken, stir them in simmer, close the kadai with a lid, chicken pieces may leave water, stir them occasionally, after a while add the green bell pepper pieces to the chicken masala (as the bell peppers get well cooked very easily its better to add them after a while)..if needed add water r else cook them with lid closed n stir them occasionally until the oil gets separated...add the curry leaves n chopped coriander leaves to the curry , put off the stove...

Serve hot..can also do this curry with Paneer instead of chicken pieces...