STM investigations on the adsorption of submonolayers of large organic molecules smaller than 6 nm were carried out on copper surfaces to compare two different deposition methods: the thermal sublimation and the pulse-injection. The blue lander, a member of the lander family, could be deposited intact with the thermal procedure, therefore it was used to test the performances of the pulse-injection. On the contrary, the bis-porphyrin, which was decomposed by the thermal procedure, was deposited intact with the pulse injection.