Abstract: A photosensitive compound as a molecular resist whose size is smaller than conventional polymer for photoresist, and which can form a nano assembly, and a photoresist composition including the same are disclosed. The photosensitive compound represented by the following formula. Also, the present invention provides a photoresist composition comprising 1 to 85 wt % (weight %) of the photosensitive compound; 0.05 to 15 weight parts of a photo-acid generator with respect to 100 weight parts of the photosensitive compound; and 50 to 5000 weight parts of an organic solvent with respect to 100 weight parts of the photosensitive compound. In the formula, n is the number of repetition of an isopropyl oxide (—CH(CH3)CH2O—) monomer, and is an integer of 1 to 40, and R is an alkyl group of 1 to 20 carbon atoms or a cycloalkyl group of 3 to 20 carbon atoms.