Cilic, the highest remaining seed in the semi-finals, saw off Gilles Muller 6-3 5-7 6-4 before Lopez battled through a rain-interrupted game 7-5 3-6 6-2 against Grigor Dimitrov on Centre Court.
It is a third Queen’s for Cilic and a second for Lopez, who lost to Dimitrov in 2014.
«It is just amazing to get to the final,» Cilic, 2012’s champion, said. «Also considering that today’s match was extremely high level. I was playing really, really good throughout all the match. Gilles was just pushing me to the limits.
«It was not easy to keep calm after not converting a lot of break points I had in that second set and then losing it, and then also, beginning of the third I had love-40 and lost that game, but eventually I got the break and really played a great match.»
«This week I was feeling really good on my serve, and especially on the shots afterwards I was playing really well. Against Gilles today I was mixing it up really good and just playing really well, really smart in some critical points. It’s just paying off nicely.»
Cilic then went on to play his doubles semi-final with Marcin Matkowski against Jamie Murray and Bruno Soares, which was moved onto Court One because of the rain delays, as he aimed to become the first man to win both titles at Queen’s since Pete Sampras in 1995.
Lopez, meanwhile, had to overcome a 45-minute delay during the second set, when he regained composure to see off Dimitrov.
«I know it was going to be a tough match against Gregor, we had a tough final in 2014,» said Lopez. «I think I was playing some of my best tennis during the whole week and hopefully I can keep that running tomorrow.
«I am so happy to be in the final here at one of the most special tournaments for me. I have wanted to win this tournament so badly for my whole career and tomorrow I have another chance, so I feel very pleased.»