A simple and efficient procedure for the synthesis of pyrazoloisoquinoline and pyrazolopyridine derivatives by one-pot three-component condensation of aminopyrazoles, aldehydes, and cycloketones in water using carbonaceous material as solid acid catalyst is described. The procedure offers several advantages such as simple experimental and work-up procedures, high yield, recovery, and reusability of metal-free solid acid heterogeneous catalyst along with tolerance of a wide range of functional groups. (C) 2015 Elsevier Ltd. All rights reserved.