Argon ion laser sensitive polymers were synthesized by the condensation of poly (4-vinylbenzyloxy) acetophenone-co-methacrylic acid [P (4-VBz) Ap-co-MA] with 4-dimethylaminobenzaldehyde or 4 dimethylamino cinnamaldehyde in the presence of alkaline catalyzer, respectively. It is found that poly (4-dimethylamino-4'-vinylbenzyloxy) benzalacetophenone-co-MA [P (4-DiMeAm-4'-(VBz) BAp-co-MA)] and poly (4-dimethylamino-4'-(vinylbenzyloxy) cinnamillidenacetophenone-co-MA) [P (4-DiMeAm-4'-(VBz) CAp-co-MA)] were highly sensitive to the 488 nm line of argon ion laser in air. These condensation copolymers were soluble in commercial developing solution for negative type presensitized plates and can be utilized as a alkaline developable photoresist. The sensitivities to argon ion laser were estimated 39 mJ/cm2 (static conditions), 46 mJ/cm2 (scanning conditions) for P (4-DiMeAm-4'-(VBz) BAp-co-MA) and 22 mJ/cm2 (static conditions), 34 mJ/cm2 (scanning conditions) for P (4-DiMeAm-4'-(VBz) CAp-co-MA), respectively.