Arwel Jones and Elwyn Williams were demoted by two grades over concerns about the way a tender had been awarded and managed for promotional work.
They won their cases at an employment tribunal last year.
The payouts have been revealed in the annual accounts for 2014-15 for the library in Aberystwyth, Ceredigion.
One was paid £71,890 in compensation and the other received a redundancy payment of £53,498 and £28,460 in compensation.
Included in the total, a sum of £88,000 is listed in the accounts under "exceptional items", and refers to the cost of fighting the employment tribunal.
In addition to the £153,000 the library has said it's legal costs were £53,000, giving a total cost of £206,00.
The accounts also reveal the library paid out £601,544 to nine staff who accepted its voluntary severance scheme last year with a further 18 due to share £752,230 this financial year.
The library also says that the costs resulting from a fire in April 2013 have had a "significant impact".
Two senior staff members unfairly dismissed by the National Library of Wales received payouts totalling £153,848, annual accounts show.