Rankin, a farmer, who coached both Caledonia and Edinburgh in the early years of professionalism, has been at Dundee for 10 years. He also coached Scotland A and Scotland Under-21. He was coach of the Scotland club international side in 2007 and 2008 and then manager of the team for the next three seasons.
Gerry Tosh, the Dundee president, paid tribute to the departing coach, saying: "Ranks will be a very hard act to follow, but he has the club's best wishes as he allows his name to go forward for the position of vice-president of the SRU.
"This 10-year period has been the most successful of the club's history and includes two cup finals at Murrayfield, winning the Division 2 championship twice and a second-place finish in the Premiership last year, leading to our participation in the British and Irish Cup this season."
Although he has not officially launched his campaign for election, Rankin is a popular and forceful character with strong opinions on the direction Scottish rugby has been taking in recent seasons.
On Monday, Herald Sport reported his criticisms of the SRU's failure to promote home-bred playing and coaching talent. If he does move into rugby governance he would be expected to become a powerful voice for the grass roots of the sport.
Rankin said: "It has been a real privilege to have been at the heart of Scottish club rugby and to have helped to establish Dundee High Rugby amongst the top clubs in Scotland, giving players an opportunity to play at the highest possible level. I leave with so many great memories and in the knowledge that the club is in a better place on and off the field, which is a great credit to all who shared and contributed to my time at Dundee.
"I am aware of the challenge facing this and so many other clubs over the final run in to the season, and remain fully committed to the job in hand and look forward to signing off in style."