If you are talking about the big picture (the guys with the bike), then it's the manga "Uso Mitai na Hanashi Desu ga" by Koshino ( https://www.mangaupdates.com/series.html?id=50892 ).
about the smaller picture (the guy with the costume at the night scene) I am afraid I can't help you much, but the art looks like KUSAMA Sakae's ( https://www.mangaupdates.com/authors.html?id=2281 ).
hope I helped!
You are lucky!!! I found the second picture as well (well I got curious too :P) It is KUSAMA Sakae's manga and it's called "Match Uri" ( https://www.mangaupdates.com/series.html?id=55633 ) but it is licensed in English (〜￣△￣)〜
noooooooo!! but thank you anyways :p
You are welcome (●'◡'●)ﾉ
what anime is this: http://www.mangago.zone/read-manga/slow_starter_ichikawa_kei/mf/sa-v2c004/pg-15/