// Attach this to a gameObject that has a renderer.
    if(renderer.material.HasProperty("_Color"))
        renderer.material.SetColor("_Color",Color.red);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Example() {
        if (renderer.material.HasProperty("_Color"))
            renderer.material.SetColor("_Color", Color.red);
        
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        if renderer.material.HasProperty('_Color'):
            renderer.material.SetColor('_Color', Color.red)