We have employed 1,7-dibromo-N,N'-ditridecyl-3,4,9,10-perylenetetra carboxylic diimide (DB-PTCDI-C13) for the development of novel n-type monolayer field-effect-transistor (FET). Functionalization of PTCDI core with long alkyl chain and bulky bromine atoms improved the solubility and made n-type monolayer FET performance possible via solution deposition processes. Annealing effect of spin coated films and drop casted films have been discussed. Liquid crystalline phase of DB-PTCDI-C13 turned out to be playing an important role in controlling the film quality and mobility. The highest mobility was 5.8 x 10(-3) cm(2) V-1 s(-1) after annealing, of which device has been then tested for doping by potassium.