The present invention relates to optionally substituted 4,5,7,8-tetrahydro-(optionally 4-oxo, 4-thioxo or 4-imino)-(1H or 2H)-imidazo[1,2-a]pyrazolo[4,3-e]pyrimidine or 4,5,7,8,9-pentahydro-(optionally 4-oxo, 4-thioxo or 4-imino)-(1H or 2H)-pyrimido[1,2-a]pyrazolo[4,3-e]pyrimidine compounds, and methods of using said compound, e.g., wherein the treatment relates to diseases involving disorders of the dopamine D1 receptor intracellular pathway, such as, among others, Parkinson's disease, depression, narcolepsy, damage to cognitive function, e.g., in schizophrenia.