Both are stories which involve a handsome guy falling in love with a boy, which is considered to be rather ugly by the others. If you found Kikoenai Koe appealing to your tastes, you will definitely like Aitsu no Daihonnmei.
Both have the ugly-cute uke and "school's most popular guy who, for some reason, fell for the ugliest guy" seme.
Both value their side characters and give them a lot of screentime, whether they have feelings for one of the main characters or not.
These series are really different, but somehow, Aitsu no Daihonmei feels like the romance verision of Majin Tantei Nougami Neuro. MTNN is a dark (But comic) detective manga about the sadistic daemon Nougami Neuro who has come to earth to eat riddles, and forces high school student Katsuragi Yako to help him capture criminals. Aitsu is the story of the "Ugly" boy Yoshida, bullied by all girls in his class because the good looking and nice Saitou (Who is acctually quite sadistic) is allways using him as an excuse to not be with the girls who keeps asking him out.
Neuro and Saitou are both double faced, and both likes and keeps tormenting thier counterparts (Neuro does it way more extreme and bizarre (Not pervy tought))
Aitsu, even if it got a yaoi tag, don't really have anny sex scenes or stuff.
Similar plot + characters:
Childhood friends / classmates from elementary school reunite in high school.
Role reversal: The kid who protected the other in the past, is now smaller and weaker.
Uke is initially reluctant to start their relationship.
These two mangas both apply the whole "uke-is-taller, stronger, and protects seme when younger" dynamic. They take place in school settings and are *utterly delightful* to read, though aitsu no daihonmei is the funnier of the two, and ren-ai houteishiki the more dramatic.
similar to 3rd and 4th story in Akanai Tobira:
unpopular and rather unattractive protagonist falls in love with the most popular guy at his high school/university.
also, the seme is kind of a sadist...