In December 2000, Nagao decided to devote all his time to composing the music and no longer appeared at live events.

After its disbanding, Nagao continued composing songs, sending demo tapes to more than fifty record companies in Japan.

Eventually, auditions were held, and he chose Tomiko Van as lead singer and Ryo Owatari as guitarist.

[2] At their one-hundredth concert, held at Shibuya AX for free, the members of DAI recognized that the fans were the same bunch that bothered to listen to them.

They also took part in choice events nationwide, including a festival in Tomiko Van's native Kumamoto Prefecture.

They continued to do public appearances all the way up to the year-end Avex Millennium Count Down 1999-2000 held on New Year's Eve in Roppongi's Velfarre club.

It was their first Top 30 hit and it was chosen as the official TV commercial song for Kanebo Cosmetics' Testimo line of products.

The next single, "Yesterday & Today" was chosen as the theme song for the drama series Nisennen no Koi,[4] which starred popular actors Miho Nakayama and Kaneshiro Takeshi and was given the primetime slot.

[2] Also in August, the single "Summer Days" was released, which would go on to become a staple at all Do As Infinity live concerts, and was used as a theme song for Fuji TV's OL Police.

Nagao decided to work behind the scenes as he was unable to manage both the production of music and the live performance and promotional campaign.

The televised performance brought Do As Infinity to an even wider audience, and helped to make their new album, New World, debut at number one on the Oricon charts.

Six commercials were made in total, the other three songs included "Tsubasa no Keikaku", "Bōkenshatachi", and "Nice & Easy"; "Boukensha Tachi" was used three times.

The following month would see the release of "Fukai Mori" (Deep Forest), which was chosen as the second ending theme song for the hit anime series Inuyasha.

The remainder of the year was spent in preparation for yet another live concert tour, which would begin in November, not long after the release of their eleventh single, "Bōkenshatachi", and their third album, Deep Forest, which debuted at number one on the charts.

January 2002 started with Van appearing on the Avex charity album Various Artists Featuring Songnation, and the release of the band's twelfth hit single, "Hi no Ataru Sakamichi", the following month.

Their following overseas was almost as huge as in their own country, drawing 500 fans to their in-store event held at the HMV CD store in Hong Kong.

They were nominated for the seventeenth annual Gold Disc Award in Japan for the best Rock & Pop album of the year and won.

The band took a short break upon returning to Japan, but released their thirteenth single in July, the double A-sided "Under the Sun / Under the Moon".

The band got busy on the concert tour of True Song and new recordings, their fifteenth single, "Mahou no Kotoba: Would You Marry Me?"

"Honjitsu wa Seiten Nari" followed the popularity of its precedent single, it was previewed in their annual summer activity, a-nation.

Tomiko met with famous American singer, Michelle Branch, during her visit in Japan to promote her album Hotel Paper, for a magazine interview and photoshoot.

Although Dai Nagao was not as active as he was in the beginning, (he did not participate in promotional events anymore) he was still the main composer behind the band.

Three days before the final concert, Dai Nagao released the last Do As Infinity song called "Trust" on the official website through Internet streaming.

The vocals featured in this song is sung by Mizushima Kana from one of Nagao's side project artists I-lulu.

Tomiko Van, the lead singer, pursued a solo career and debuted on March 29, 2006, with her album, Farewell.

The band's 28th single "Mysterious Magic" was released on December 10, 2014; the song was used as an opening theme to the anime series Fairy Tail.

Saiko Kawamura, which is a joint pen name of Jun Harada and Kayoko Shinchi, and Naoto Suzuki also write songs besides them.

[12] For the second contest, held between September 1 and October 31, 2009, three were selected, two of which appear on "∞2": "Everything Will Be Alright" by Shohei Ohi, and "Haruka" by Fumiyasu Sueoka;[12] the song composed by the third winner, Nobuhisa Fujii, has yet to be revealed.