Besides, he also wants to live up to the principle of "never forget the pure heart of a boy and fight on". As a result, he combined the words “Crazy” and "Boy” and called himself CRAZYBOY. As CRAZYBOY, Elly began to made guest appearances in the works of other famous musicians. He joined in producing his new song, "HELLA RICH feat. CRAZYBOY", which was released in July 2016. His collaboration with Dancehall Reggae group "Around The World" was released shortly after in the same month. On February 24, 2017, Elly released his first mini-album "NEOTOKYO EP" as CRAZYBOY, earning the #1 spot on the weekly music downloading charts of four major media-service providers in Japan. His second mini-album "NEOTOKYO Ⅱ EP" was released on July 7, and a DVD/CD package with recorded live performances, music videos and songs titled "NEOTOKYO WORLD" was released on September 21. On January 19, 2018, he released his third mini-album "NEOTOKYO III EP". In February, he joined Snoop Dogg, and Yultron in producing the international collaboration "BOW DOWN FT. CRAZY BOY from EXILE TRIBE". After the release of his fourth mini-album "NEOTOKYO IV EP" on April 27, his first "Best of" album "NEOTOKYO FOREVER" was released on July 4. To conclude his solo activities in 2018, Elly went on his first solo tour "CRAZYBOY presents NEOTOKYO ～THE PRIVATE PARTY 2018～" from July 9–27. On July 3, 2019, Elly performed in Los Angeles for the first time in his career, at OTAQUEST LIVE. This music festival aims at bringing Japanese pop music to America. On June 22, it was announced that Elly had migrated record labels from Rhythm Zone to LDH MUSIC for his solo activities. It was also announced that his rapper alias, CRAZYBOY, was updated to CrazyBoy. He also made a change to his personal logo as a rapper. On August 23, Elly released his first digital single, "PINK DIAMOND". On September 12, it was announced that Elly would feature on the Japanese version of Jessica Jung's new single "Call Me Before You Sleep", aiming to be released on October 19.