Despite the few interactions between Splendid and The Mole, it's 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 about 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 for Splendid 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 put them to work together. When The Mole accidentally took a photo that would reveal Splendid's secret identity, the latter spent the whole episode chasing The Mole. Splendid even broke Petunia in half and beat up Giggles by mistake, implied to have intended to do that with 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).
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, who also aren't fond of Splendid.