Troicki, who played two full matches on Friday, had to come from a set and 4-2 down to beat Teymuraz Gabashvili 3-6 6-4 6-4 and clinch his place in a second successive final at the Australian Open warm-up, which he won as a qualifier last year.
Dimitrov was better rested having only had to play out the last few games of his 4-6 6-3 6-4 quarter-final victory over Alexandr Dolgopolov, which was stopped by a violent thunderstorm that wreaked havoc with the schedule on Thursday.
The Bulgarian has long been the next big thing of men's tennis and hopes that he might be on the brink of fulfilling his potential were fuelled by an inspired, if ultimately losing, performance against Roger Federer in Brisbane last week.
The 24-year-old again impressed with his flair from the start on Friday as he raced through the first set in 37 minutes.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Muller ramped up his serve to battle back in the second set but Dimitrov kept his composure through the tiebreak to seal victory and his first final since October 2014 with a rasping backhand crosscourt pass.
"The shots were working today," Dimitrov said.
"It's been a while since I've been in a final and I'm happy, I'm not going to hide that. But my job's not done yet.
"I thought my mental toughness was pretty good today."
Troicki had launched a comeback to beat Nicolas Mahut 4-6 6-3 6-3 in his quarter-final on Friday morning but that was nothing compared to the depths he dug himself out of in his afternoon match.
Russian Gabashvili looked well on his way to a first ATP final when he led 6-3 4-2 but the Serbian returned from a short rain break to win the next four games and level up the contest.
Troicki was broken when he served for the match at 5-2 in the third set and but made no mistake with his second attempt, wrapping up the victory with an ace.
Top seed Bernard Tomic had earlier retired from his quarter-final while trailing Gabashvili 6-3 3-0 and made it clear in remarks to the umpire that his focus was on next week's Australian Open.
Rain prevented any matches being completed on Thursday so Tomic, if he had beaten the Russian, would have had to play a semi-final later on Friday, as well as potentially Saturday's final.
"I was just feeling a little bit sick last night and was very difficult to play two matches today," Tomic said.
(Editing by Ed Osmond)
