I am not to sure what your question is. Are you asking can IC by its self, not in a package, be connected to a circuit on a PCB? Yes but it would need power and ground, etc connections also. An IC in a package like a DIP can.
For example in the CDI (capacitor discharge ignition) circuit,that I am currently working on, the optoisolator (yellow) has the transistor directly connected to another device (MOSFET) on a another PCB.