new Color() not working properly?

Hellooo

Didnt thought that would be a Problem, but I experienced a problem with coloring objects.

I use:

 inst.renderer.material.SetColor("_Color",BuildGreen);

To Color an Instantiated Object Green. But it shouldnt be complely green (not like a neonflash green, where you cant see the object anymore)

So I created my own Color

 Color BuildGreen = new Color(0,255,0);

I also tried

 Color BuildGreen = new Color(0,255,0,255);
 Color BuildGreen = new Color(0,255,0,0);
 Color BuildGreen = new Color(0,255,0,100);

Its always the neonflash green result, no matter what. However, if I use Color.green.... its working, the object is still visible, even if its too much green. So why isnt it working properly? What I did wrong / have to change?

Thanks in advance.