An efficient and environmentally benign isocyanide based domino protocol has been presented for the synthesis of structurally diverse spiroheterocycles, spiroannulated with imidazothiazole and imidazothiadiazole, involving the three component reaction of 2-aminobenzothiazole/2-amino-1,3,4-thiadiazole, cyclohexyl/tert-butyl isocyanides and isatines/cyclic carbonyl compounds catalyzed by recyclable and reusable nanocrystalline TiO₂.