A communication device includes an instant messaging software (IMS) and a sensor. When an object nearby the sensor is detected, a trigger signal is generated by the sensor. When the IMS is activated to communicate with a target contact and the trigger signal is generated, communication content between a user of the communication device and the target contact within a predetermined time interval is analyzed to determine whether or not the communication content includes a phone number. If the communication content includes a phone number, a phone call between the communication device and the phone number is made.