While the top of Mitsubishi Zaibatsu (financial clique), Yanosuke IWASAKI and a doctor, Shokichi NAGAYO were Shojiro's adopted son-in-law, Koyata IWASAKI of Mitsubishi, Toshiya IWASAKI, a founder of Asahi Glass company and Teruya IWASAKI, a pioneer of railway enthusiasts were Shojiro's grandchildren.
三菱財閥の総帥・岩崎弥之助と医師・長與稱吉は象二郎の娘婿であり、三菱の岩崎小弥太と旭硝子の創業者・岩崎俊弥、鉄道ファンのパイオニア・岩崎輝弥は象二郎の孫にあたる。