Scripting Reference
Color.Color

static function Color (r : float, g : float, b : float, a : float) : Color

Description

Constructs a new Color with given r,g,b,a components.

JavaScript 
    var color : Color = Color(0.2, 0.3, 0.4, 0.5);
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Color color = new Color(0.2F, 0.3F, 0.4F, 0.5F);
}
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public color as Color = Color(0.2F, 0.3F, 0.4F, 0.5F)

static function Color (r : float, g : float, b : float) : Color

Description

Constructs a new Color with given r,g,b components and sets a to 1.

JavaScript 
    var color : Color = Color(0.2, 0.3, 0.4);
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Color color = new Color(0.2F, 0.3F, 0.4F);
}
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public color as Color = Color(0.2F, 0.3F, 0.4F)