public Material[] materials = new Material[2];

void Awake()
{
    string sceneName = SceneManager.GetActiveScene().name;
    if (sceneName.Equals("RedScene"))
    {
        GetComponent<MeshRenderer>().material = materials[0];
    }
    else if (sceneName.Equals("GreenScene"))
    {
        GetComponent<MeshRenderer>().material = materials[1];
    }
}