Use transistors for controlling two LEDs
Something like this should work:







simulate this circuit &ndash; Schematic created using CircuitLab

If the signal from the MCU is Low, the red LED will be on, if High, the green LED will be on.

An NPN transistor (such as 2N3904) will conduct when the base is more positive than the emitter.  A PNP transistor (2N3906) will conduct when the base is more negative than the emitter. Resistors are required in the base lead to limit the base current.