It has a single narrow, dark green leaf and one or two violet flowers with purplish tips and darker veins, and a yellow lobe on top of the anther.

The side lobes are yellow and curve forwards with rough or hairy edges.

[2][3] Thelymitra × mackibbinii was first formally described in 1881 by Ferdinand von Mueller and the description was published in the Australasian Chemist and Druggist from a specimen collected near Maryborough.

[5] This orchid was previously known as a natural hybrid but is currently recognised as the species Thelymitra mackibbinii.

[3][6] The brilliant sun orchid grows in open forest and woodland in the goldfields region of Victoria, near Stawell, St Arnaud and Maryborough.