How to send a new iMessage throug Applescript. For retrieve the contactname select your contact from list then SHIFT+CMD+I

Applescript to send new iMessage

tell application "Messages"

   set isAppRunning to false
   tell application "System Events"
       if (exists process "Messages") then
           set isAppRunning to true
       end if
   end tell
   
   if isAppRunning is false then
       activate
   end if
 
  set theBuddy to buddy "contactname@imac-di-contactname" of service "bonjour"
	send "test" to theBuddy
end tell