An alkali-soluble resin having a polyaromatic group and a photosensitive composition comprising the alkali-soluble resin. The alkali-soluble resin comprises the following recurring units: wherein each of R1, R2, and R3, independently, is H or CH3; R4 is a substituted or unsubstituted polyaromatic derivative containing carbon and optionally containing one or more heteroatoms of oxygen, nitrogen and sulfur; X is alkyl, benzyl, or hydroxyl; each of n1 and n2, independently, is an integer of 0–8; and a, b, and c are integers when a and c respectively are not zero.