Lennon is keen to add another forward to his options with Gary Hooper having left for Norwich, and the deadline for Champions League signings comes on Monday night.
He watched the Finland international in action when they beat Slovenia 2-0 in midweek but Celtic's initial bid for Pukki was rejected and the German side are believed to be holding out for a fee of £2.5million.
Celtic have also been linked with Heerenveen striker Alfred Finnbogason but reports earlier this week suggested their hopes of landing him were fading because of the Dutch club's £5million valuation.
"Teemu is a player that we like," said Lennon. "I was out watching him on Wednesday and we are trying to bring him in. It's not easy at this stage of the window.
"With a lot of clubs in Champions League position, similar to us, they won't want to let players go but we are very determined to bring players in and we are working hard in the background to do that.
"(Our bid has not been accepted) but negotiations are hopefully on-going. We will go again.
"There is a limit for all players. What we are looking for is value for money. While we do have money to spend, we are not going to throw it at things just to justify our position.
"We want players who will make us better and at what we feel is the right price for the player.
"We do think Pukki is a very intelligent, sharp. His movement is excellent and his first touch is very good, very similar to Hooper. I don't know if he'd score as many as Gary but he'd certainly score his fair share of goals."