ColorBlock.pressedColor

public Color pressedColor ;

Description

Pressed Color.

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public Button button;
    public Color newColor;

    void Start()
    {
        //Changes the button's Pressed color to the new color.
        ColorBlock cb = button.colors;
        cb.pressedColor = newColor;
        button.colors = cb;
    }
}