Thanks to all for their valuable suggestions.
QtSerialPort library is an added feature for Qt5 .It is always advisable to use inbuilt library created by qt.
Since QtSerialPort library is not supported by Qt 4.7 or lower version.
I was able to design an Application using Qt 4.7 itself. It needs to include library for serial communication as Qt 4.7 has no in-build library for serial port. I did it using following link :
For Windows add the "qextserialport-1.2rc" (download using following link)
Qextserialport Example - Hyperterminal Windows
For Linux add library "myser1.zip" (download using following link)
Qextserialport Example - Hyperterminal Linux
Above links also includes the application for Serial Communication for respective OS. Adding the libraries from the above application helped me designing an Application for my task.
The above answer will help the developers who are not permissible to upgrade Qt-tool due to company policy etc.
Hope this will help others to solve the similar problems.