The work is focused on using butanol as gasoline replacement in a Direct Injection Spark Ignition engine. The impact of this fuel on the early stages of the combustion processes was investigated using optical diagnostics and conventional methods in a transparent single cylinder engine. The engine was operated in homogenous charge mode at 2000 rpm, with commercial gasoline and pure n-butanol fueling. High spatial and temporal resolution visualization was applied in the first phase of the combustion process in order to follow the early flame development for the two fuels. The optical results were completed with conventional measurements of thermodynamic data. Moreover, UV emission spectroscopic investigations were carried out to evaluate the temperatures during the spark discharge and the initial flame kernel. The applied methodology used the intensity ratio of emission bands related to CN and OH radicals. The vibrational  and rotational temperatures estimated in the early combustion stages were compared with those calculated following a thermodynamic approach.