This paper focuses on the inhibition and the promotion efficiency of inhibitors in a novolac resin respecting dissolution rate into a developer. Several t-Boc derivatives of bis-phenols, which have different substituent groups on their methyl carbon, were synthesized as model compounds. Their properties were evaluated in the case of adding to a novolac resin. It was observed that the bulky substituent groups provided the inhibitors with a high inhibition efficiency, though polarity group such as esters, impaired inhibition efficiency. On the contrary, the decomposed form of inhibitor which containing ester group, promoted dissolution rate of resist efficiently. The authors have reported the high performance of the t-Boc derivative, named CP-Tboc which contained a lactone ring as a bulky substituent group. The decomposed form of CP-Tboc in the exposed area exhibits high promotion efficiency. To compare the promotion efficiency of CP-Tboc with an inhibitor having ethyl ester group, it was confirmed that the hy rolysis of lacton ring during the development increases the dissolution rate. This high promotion ability is advantages in that it avoids the influence of cross-linking of matrix polymer caused by EB exposure.