Despite the few interactions between Splendid and The Mole, it is shown that they are not fond of each other, likely due to Splendid's impatience and The Mole's blindness always clashing, generating a conflict. It could be argued that their conflict is one-sided, as The Mole shows less signs of disliking Splendid than vice-versa.
Episodes Suggesting a Conflict
Splendid was so focused on his laundry that he didn't care that he killed The Mole (and several others) with the whirlpool of lava he caused.
When Splendid's laser stopped at a red light, The Mole became annoyed at Splendid for slowing down the traffic. In retaliation, Splendid killed The Mole with the laser, thus becoming Splendid's first intentional kill.
In this episode, their conflict is more highlighted, as Splendid showed annoyance when Lumpy made them work together. When The Mole accidentally took a photo that would reveal Splendid's secret identity, the latter spent the rest of the episode chasing down The Mole. Splendid even sliced Petunia in half and beat up Giggles by mistake, implying that he intended to do that to The Mole. On the other hand, The Mole saved Splendid's identity from being revealed in the end of the episode (though this may have been by accident, as The Mole saved it by walking into the darkroom at the wrong/right time as the pictures were being developed).
Splendid was so focused on his book that he didn't care about saving The Mole, Cuddles, or Giggles from the tornado.
Episodes suggesting a friendship
The Mole, along with everyone else, sat down to attend Splendid's speech. Note that Lifty, Shifty, and Pop were there, all of who also aren't fond of Splendid.