Jarco

Jarco is the het ship between Jackie Lynn-Thomas and Marco Diaz from the ''Star vs. the Forces of Evil.

Canon
However, in "Bon Bon, the Birthday Clown", they officially start dating and go together in a school dance, which is a mess, but still are able to enjoy their date by Jackie telling Marco that she likes him because even though he is always messing up, he picks himself up and keeps moving forward and offers to teach him how to ride on a skateboard which two helmets and board she had hidden in her dress, and the two hold hands and skate together, unaware that they're spied on by a jealous and heartbroke Star, who unintentionally zaps one of their skateboard wheels and trips them. Despite their fall, they still had a good time and share their first kiss, but Marco is distracted by the sight of a red moon and quickly realizes that Star is in trouble and the two rush to help her, and manage to save Star from being sucked into a portal but Ludo manages to get away with Glossaric and the book, and after making sure that Star is okay, Marco rushed towards Jackie.

In "Just Friends", Marco, Star and Jackie go together to a concert of their favorite band Love Sentence and when they start singing the song "Just Friends", Jackie takes Marco's hand and asks him to dance with her and then they kiss, much to Star's heartbreak, but she reassures Marco she's okay and he reunites with Jackie, who kisses him again.

In "Starcrushed", Marco and Jackie go together in an end of the year party, where she tries to cheer him up when he seems down, and later is shocked when Star admits in fron of everyone that she has a crush on Marco too and sees Marco rushing after Star, who has decided to return to Mewni.

However, Marco and Jackie's relationship reaches to an end as Marco had spent his summer vacation in Mewni helping Star and has become distanced from his friends and family on Earth, and Jackie even pointed that he didn't even asked about her summer and it seemed that he never came back from Mewni. To which Marco decided to make it up to her by taking her on a date in a seafood restaurant, where he won her a prize in an arcade game and later they freed a lobster from the restaurant and back into the sea, and then sat down to watch the sunset together in the pier, with her starting they could have freed all the lobster from the restaurant and Marco said that he felt like he's finally came back to Echo Creek and they embraced but then Jackie noticed something and asked Marco to take off his shirt with surprised him, making him blush, but she discovered he's still wearing the cape he was given in Mewni and gently asked him to sit down and talk, and Jackie tells him that was a great day and that she appreciates he's trying but that if he was forcing himself to stay on Echo Creek just to make her happy, both of them would would be unhappy and decides that it's a good time to let him go, but Marco takes her hand and tells her he wants their relationship to work and calls her his best friend, which briefly saddens Jackie, who tells him that both of them know that she isn’t, and with a kiss on the cheek, tells him to stay cool, before leaving on her skateboard, which makes Marco cry and decides to go back to Mewni.

A long time after their break up, Jackie went and studied abroad in France. While Marco worried he wasn't a good boyfriend to her. She returns in "Britta's Tacos" where she reunites with Marco, greeting him with a friendly punch in his arm and reveals her new girlfriend to him. Jackie laughed when Marco admitted his worries about not having been a good boyfriend and reassured that Marco was "standard", but that she enjoyed her time with him and that even if their relationship didn't work, they still could be friends. And helps Marco to get two holes in his card to get a prize in the taco restaurant and before leaving, she tells him that Star is a special girl and tells him to "not mess that one up".