win32gui get the current active application name

Install WMI package first (and pywin32 of cause):

pip install wmi

Then:

import win32process
import wmi


c = wmi.WMI()


def get_app_path(hwnd):
    """Get applicatin path given hwnd."""
    try:
        _, pid = win32process.GetWindowThreadProcessId(hwnd)
        for p in c.query('SELECT ExecutablePath FROM Win32_Process WHERE ProcessId = %s' % str(pid)):
            exe = p.ExecutablePath
            break
    except:
        return None
    else:
        return exe


def get_app_name(hwnd):
    """Get applicatin filename given hwnd."""
    try:
        _, pid = win32process.GetWindowThreadProcessId(hwnd)
        for p in c.query('SELECT Name FROM Win32_Process WHERE ProcessId = %s' % str(pid)):
            exe = p.Name
            break
    except:
        return None
    else:
        return exe

Think this will do the trick

import psutil, win32process, win32gui, time
def active_window_process_name():
    pid = win32process.GetWindowThreadProcessId(win32gui.GetForegroundWindow()) #This produces a list of PIDs active window relates to
    print(psutil.Process(pid[-1]).name()) #pid[-1] is the most likely to survive last longer


time.sleep(3) #click on a window you like and wait 3 seconds 
active_window_process_name()

assuming you have installed psutil and win32 modules

Run this program to get a better understanding

import threading, win32gui, win32process, psutil
from tkinter import *
root = Tk()
s = StringVar()
def active_window_process_name():
    try:
        pid = win32process.GetWindowThreadProcessId(win32gui.GetForegroundWindow())
        return(psutil.Process(pid[-1]).name())
    except:
        pass
def to_label():
    global s
    while True:
        s.set(active_window_process_name())
    return

Label(root,textvariable=s).pack()
if __name__ == "__main__":
    t = threading.Thread(target = to_label)
    t.start()
    root.mainloop()