Goof: When the invisible robbers are exiting "Fort Metropolis", they and their weapons are invisible (since all you can see is the "muzzle fire". This should be impossible since they are wearing invisible suits over their bodies, not the weapons themselves.
Goof: The evil Invisible Man said that the vault he was putting Lois and the others in only had two minutes worth of oxygen left. A vault as large as the one in the gold depository would have held much more than just two minutes' worth of oxygen, especially since the door had been standing open with the air circulating for several minutes at least.
Phosphorus itself is not a phosphor; it is highly reactive and gives off a faint luminescent glow when mixing with oxygen. The glow is actually caused by the very slow burning of the phosphorus, but without a flame or any heat measurable amount of heat.
The Superman toys at the Kent's are playing the Lois and Clark theme.
The opening teaser for this episode features cameos by several DC Comics writers who, at the time, were working on the "Death of Superman" story arc.
Nitpick: In the company name Jackson Phosphorous, both on the sign and the bag of phosphorus powder, the word "phosphorus" is spelled incorrectly. As a side note, it might be that the company's name Jackson comes from Jackson Beck, who did the voice-over of the phrase "It's a bird! It's a plane! It's Superman!" to introduce the Superman radio show.
Lois: So, what you're trying to say is that another invisible man...
Helene Morris: (interrupting) ...is impersonating my invisible man!
Clark: (to Lois) Superman on TV? I don't think so.
Clark: Lois has a pair of Superman pajamas.
Martha: You saw Lois in her pajamas?
Clark: No! Well yes, but it was an accident, when her robe came undone.
Clark: But marriage is about sharing everything you have, even if you don't feel like it.
Lois: So is divorce. Ask my mother.
Lois: (About Cat's quite revealing dress) Couldn't you afford the whole dress?
Cat: Less is more, darling. Sometimes.
Lois: You know, I never thought I would say this, Clark, but you and I have something in common.
Clark: What's that?
Lois: Superman. You want to fly like him, and I want to fly with him.
Superman: You'll always be special to me, Lois.
Lois: I will?
Superman: You're the first woman who ever... interviewed me.
Leslie Jordan, who plays Alan Morris (the "good" invisible man) also appears in the second season episode "A Bolt From The Blue" as "William Wallace Webster Walldecker".