Is sp2d hybridisation possible in coordination chemistry?If yes please give examples with box diagram of hybridisation.

The sp2d hybridization is yet contradictory, it's a outer orbital hybridization and can't assure it happens or not but yes dsp2, the inner orbital hybridization can happen.

Let's take an instance of coordination complex [Cu(NH3)4]2+ , copper tetraammine(II) ion. Somewhere mentioned it's a sp2d while elsewhere mentioned it's a dsp2 hybridization, Most of us alongwith me would utter as dsp2 but unfortunately I only got a glimpse of possibility of sp2d hybridization, someone in cyber world has mentioned only that she found in a book written in some other language (without any info of it). So can't say but most probably it's dsp2.

And so to perceive about spd2 hybridization we have to search in International level with the Chemistry books of all languages to assure whether it happens or not.