Shinkyoku Soukai Polyphonica

Corticarte has the same attitude as Shana, it's kinda funny how similar they are. They are different in the aspects of the plot, but they have a similar feel.  

I wonder how this was not mentioned earlier ... If you want to watch an anime close to NC than i think SSP would do the job - the genres are preatty much far apart one eachother since NC its more science of life/comedy and SSP its Fantasy but none the less the music in both of them its tottaly awesome. 

Similar looking main heroines in the same non human love conflict, both have loli and full forms. Similar indecisive main heros. Takes place in a special trainig school setting. 

Same concept as Polyphonica; Conductor <-> Dantist, Musicart <-> spirit Takt <-> Phoron, Destiny <-> Corticarte 

Male and Female Lead. A bit more serious than Nodame Cantabile,but has its funny moments Music is pretty much a main part of the series. 

both anime base on a game poly phonica is a visual novel and ar tonelico is considerd one too also dantist and reyvateil use both music to support their allies but ar tonelico use song magic there quite similar when i first watch poly phonica i remember ar tonelico 

Both anime are set in alternative version of present day world. Unlike in reality, supernatural beings are common in both titles. In Yozakura Quartet we have a city that is a refuge for youkai, in Polyphonica a city when humans and spirits live together. Both also have similar theme of office dealing with the supernatural denizens of the cities as the main theme.  

in both human make contract with non-human and fight tohether 

One unique teenage boy out of everyone else gets paired up with a long, crimson-haired girl at school which deals with mystical spirits.  

both teamed up with famous partners this show also involves contracts