In order to obtain selective protein kinase C (PKC) inhibitors competitive toward ATP, an efficient synthetic process of a series of monoindolylmaleimide derivatives was achieved. As expected from the PKA-PKC homology, the PKC selectivity was promoted by addition of amine chains on the maleimide ring. The most active derivative could be used as starting molecule for the preparation of specific PKC isotype inhibitors according to the bisubstrate concept.