I bought two smart phones for my father and sister in Europe. Will the customs officer in India (Chennai) give any trouble if I carry two new unopened smart phones with the box in my hand luggage? Also, i'm a student, does this give me any advantage over it?
The situation is a little complicated and there a few things you must consider. First of all I'm going to tell you about all the legal prospects of this situation and what can happen if then open up your bags and find two packaged phones inside.
Take a look at this great answer already posted here. Now, since these are two packaged phones, despite being underneath your limit of Rs. 33000, they are items which can be re-purposed by anyone else which quite honestly is what you are doing here because of the fact that you are giving them to your parents. Even though you don't plan to sell them, you still won't take them back with you, so they are technically imported into the country.
Now, one second thought, you could take the phones out of the packages and put them either in your suitcase or your hand-luggage.
Now, is this fool-proof? Obviously No. And the reason it isn't is because you are importing things into the country and if they ask you to pay import duty on it, your only argument can be, "Hey these are for my own use!" Now, if the two phones are packaged, this argument is far less convincing. Otherwise they might let you thru without much issue.
Keeping this in mind, if the phones are in your hand luggage and are not packaged, you should be fine. If you decide to take them in your luggage without the packaging or packaging separately in different luggage or something, that would be pretty fine too! If you do decide to take them as packaged goods, that's up to your own risk.