Gerard Gallant didn’t mince words Thursday night when talking about Artemi Panarin and Vincent Trocheck, two-thirds of a line the Rangers coach thinks is supposed to be contributing more than it has.

Their chemistry “better get better,” Gallant said following the Rangers’ 3-1 loss to the Bruins on Thursday. The second line has been sufficient on offense, but Gallant said it requires “a lot more” on defense. Panarin and Trocheck must produce.

And then came Gallant’s stinger: “They should’ve scored three or four goals tonight, but they could’ve given up four or five just as easy. And that’s not what coaches want.”

With the Rangers now past the midway point of their season, and third in the Metropolitan Division with 57 points, their season-long conundrum of what combination to use on the second line — and what to do with Panarin and Trocheck, once a promising pair — has continued. Panarin has one goal in his last seven games, while Trocheck has scored just once since the calendar flipped to 2023.

Their struggles, especially on defense, have sparked conversations about what combination to try next — including Filip Chytil, as The Post’s Larry Brooks proposed — but there is no solution yet. The Rangers have allowed scoring chances and odd-man rushes to the point at which the second-year coach has started plugging other players in, such as Jimmy Vesey on Thursday, to find a group that works.

Trocheck and Panarin finished -2 and -1, respectively, against the Bruins, and were on the ice together for Boston’s first goal. On that one, the  Rangers couldn’t clear the puck along the boards, possession cycled around to the other side and Pavel Zacha tipped in a shot from David Krejci.

Trocheck was also skating when the Bruins scored their second goal during the second period. That time, he left space for Patrice Bergeron, who fired a shot past Igor Shesterkin.

Initially, as the season inched through its first month and into the second, the chemistry issues between Trocheck and Panarin appeared to be contained to just one end. Panarin told The Post’s Mollie Walker in November that “we’re not scoring enough five-on-five,” which is what he worried about.

“But again, if you’re not worried about hockey, you probably won’t find a way,” Panarian said during the Rangers’ western trip that month. “We’re trying to find ways, that’s why I was watching [film] and all that stuff. Try to figure out what we can do better. I hope it’s just in time for us. We’ll find it someday.”

That was supposed to come a lot sooner, though. In his introductory press conference after Trocheck signed a seven-year, $39.375 million deal entering the 2022 season, he and the Rangers shared their vision about the 29-year-old slotting next to Panarin as the  No. 2 center. It represented a chance Trocheck said he “never really had in my career,” but something he said “everyone would dream of.”

That connection to Panarin, in addition to a reunion with Gallant as his coach, were selling points for Trocheck. And in just the second game of the season against the Wild, their potential flashed. A pass from Trocheck to Alexis Lafreniere ended up on Panarin’s stick for a goal to close the first period. In the third period, after Marc-Andre Fleury saved an initial shot, Panarin backhanded a cross-ice pass to Trocheck for a one-timer that snapped into the net.

The pair have continued to get opportunities to skate alongside each other in the months since, opening around two-thirds of the Rangers’ 48 games on the same unit. The third member on their line, however, has rotated between Lafreniere, Barclay Goodrow, Julien Gauthier, Vitali Kravtsov, Kaapo Kakko, Sammy Blais and Vesey at various points  this season, according to Natural Stat Trick.

But after some consistency with Kravtsov since the start of the new year, the latest pivot back to Vesey mid-game against the Bruins kickstarted the shuffling process once again.

“They create offense, they get good chances,” said of his second line, “but we’re not gonna beat good teams if they continue the chance-for-them, chance-for-us, two-for-them, one-for-us.”