I am traying to add node color and other material property to my pop up panel, but i was only able to add the Material Viewpor Properties so far.
Also, how do one go about finding out this? I was able to figure out the viewport properties, but this one my trial and errors didn't work, the source code seems to be quite more complex.
You need to get a reference to that material, then its node tree, then the principled bsdf node, and finally the color input field.
First make sure you have python tooltips enabled in your preferences :
And then you can get the path to most fields just by hovering over it or with right click > Copy data path.
See this question for more information.
In your case you could access this particular field from this particular material with :
import bpy
def draw(self, context):
layout = self.layout
# The name is case-sensitive :
mat = bpy.data.materials["Material.005"]
# Assuming you didn't rename the bsdf shader :
principled = mat.node_tree.nodes["Principled BSDF"]
# Add the property in the layout. This will automatically create a color field.
# You can access inputs / outputs directly with their index or with their name as a string
layout.prop(principled.inputs[0], "default_value", text="Color") # Text argument is optional
Result :
